Three-dimensional semiconductor memory devices and methods of fabricating the same

ABSTRACT

Three-dimensional semiconductor memory devices and methods of fabricating the same. The three-dimensional semiconductor devices include an electrode structure with sequentially-stacked electrodes disposed on a substrate, semiconductor patterns penetrating the electrode structure, and memory elements including a first pattern and a second pattern interposed between the semiconductor patterns and the electrode structure, the first pattern vertically extending to cross the electrodes and the second pattern horizontally extending to cross the semiconductor patterns.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. non-provisional patent application is a continuation of U.S.patent application Ser. No. 16/859,437, filed Apr. 27, 2020, which is acontinuation of U.S. patent application Ser. No. 15/681,050, filed Aug.18, 2017, which is a continuation of U.S. patent application Ser. No.14/796,569, filed on Jul. 10, 2015, now U.S. Pat. No. 9,768,266, whichis a continuation of U.S. patent application Ser. No. 13/972,533, filedon Aug. 21, 2013, now U.S. Pat. No. 9,564,499, which is a continuationof U.S. patent application Ser. No. 13/072,078, filed on Mar. 25, 2011,now U.S. Pat. No. 9,536,970, which claims priority under 35 U.S.C. § 119to Korean Patent Application Nos. 10-2010-0027449, filed on Mar. 26,2010, 10-2010-0055098, filed on Jun. 10, 2010, 10-2010-0084971, filed onAug. 31, 2010, 10-2010-0064413, filed on Jul. 5, 2010, and10-2010-0064415, filed on Jul. 5, 2010, each filed in the KoreanIntellectual Property Office (KIPO), the entire contents of each ofwhich are hereby incorporated by reference herein.

BACKGROUND 1. Field

Example embodiments of the inventive concepts relate to semiconductordevices and methods of fabricating the same, and more particularly, tothree-dimensional semiconductor memory devices includingthree-dimensionally arranged memory cells and methods of fabricating thesame.

2. Description of the Related Art

A 3D-IC memory technique may be used for increasing a memory capacity.3D-IC memory technique refers generally to technologies related toarranging memory cells three-dimensionally. In addition to a 3D-ICmemory technique, a memory capacity may be increased through (1) apattern miniaturization technique; and (2) a multi-level cell (MLC)technique. However, the use of a pattern miniaturization technique maybe limited due to high cost and the capacity increase achieved by theMLC technique may be limited to the number of bits to be increased ineach cell. The pattern miniaturization technique and the MLC techniquesmay be combined with the 3D-IC technique, in terms of realizing a moreincreased memory capacity, and may be expected to develop separatelyfrom the 3D-IC technique.

One 3D-IC technique is a punch-and-plug technique. The punch-and-plugtechnique includes sequentially forming multi-layered thin layers on asubstrate and then forming plugs to penetrate the thin layers. Throughthis technique, without a drastic increase of manufacturing costs, amemory capacity of a three-dimensional memory device may be achieved.

SUMMARY

Example embodiments of the inventive concepts may providethree-dimensional semiconductor devices increasing thicknesses ofthree-dimensionally-arranged conductive patterns, three-dimensionalsemiconductor devices reducing resistances of three-dimensionallyarranged conductive patterns, three-dimensional semiconductor devicespreventing and/or decreasing a reduction of operating current and anincrease of string resistance, and methods of fabricatingthree-dimensional semiconductor devices preventing and/or decreasing areduction of operating current and increase of string resistance.

According to example embodiments of the inventive concepts,three-dimensional semiconductor devices may include an electrodestructure with sequentially-stacked electrodes and disposed on asubstrate, semiconductor patterns penetrating the electrode structureand memory elements including a first pattern and a second pattern andinterposed between the semiconductor patterns and the electrodestructure, the first pattern vertically extending to cross over theelectrodes and the second pattern horizontally extending to cross overthe semiconductor patterns.

In some example embodiments, the second pattern may be substantiallyformed with a conformal thickness on a top surface and a bottom surfaceof the electrode and a sidewall of the electrode adjacent to thesemiconductor pattern. In other example embodiments, thethree-dimensional semiconductor device may further include interlayerinsulating layers interposed between the electrodes at a verticalposition, the first pattern continuously and vertically extending frombetween the semiconductor pattern and sidewalls of the electrode to beinterposed between the interlayer insulating layer and the sidewalls ofthe semiconductor pattern and the second pattern continuously andhorizontally extending from between the semiconductor pattern andsidewalls of the electrode to be interposed between the interlayerinsulating layer and horizontal surfaces of the semiconductor pattern.

In still other example embodiments, the three-dimensional semiconductormay further include a capping layer disposed between the semiconductorpattern and the interlayer insulating layer, the capping layer beingformed of a different material than the interlayer insulating layer. Ineven other example embodiments, the capping layer vertically may extendto be disposed between the electrode and the semiconductor pattern and athickness of the capping layer may be thinner between the electrode andthe semiconductor pattern than between the interlayer insulating layerand the semiconductor pattern. In yet other example embodiments, thesecond pattern directly may contact a sidewall of the first pattern andthe capping layer may include portions separated vertically by thesecond pattern.

In further example embodiments, the first pattern and the second patternmay be substantially the same in terms of at least one of a chemicalcomposition or an electrical property. In still further exampleembodiments, two kinds of atoms having the highest content of the secondpattern may be identical to those having the highest content of thefirst pattern. In even further example embodiments, the memory elementmay include a charge storing layer, a tunnel insulating layer, and ablocking insulating layer, the tunnel insulating layer including atleast one insulating layer and being interposed between the chargestoring layer and the semiconductor pattern, the blocking insulatinglayer including at least one insulating layer and being interposedbetween the charge storing layer and the electrode.

In yet further example embodiments, the first pattern may include thetunnel insulating layer and the second pattern may include the chargestoring layer and the blocking insulating layer. In yet further exampleembodiments, the first pattern may include the tunnel insulating layerand the charge storing layer and the second pattern may include theblocking insulating layer. In yet further example embodiments, the firstpattern may be formed of a different material than the charge storinglayer and further may include a capping layer interposed between thecharge storing layer and the blocking insulating layer. In yet furtherexample embodiments, both the second pattern and the first pattern mayconstitute one of the tunnel insulating layer, the blocking insulatinglayer, and the charge storing layer.

In yet further example embodiments, the second pattern and the firstpattern may contact each other between the electrode and the sidewallsof the semiconductor pattern and two kinds of atoms having the highestcontent of the second pattern may be identical to those having thehighest content of the first pattern contacting the second pattern. Inyet further example embodiments, at least one of insulating layersconstituting the tunnel insulating layer and at least one of insulatinglayers constituting the blocking insulating layer may be formed ofmaterials having a higher band gap than the charge storing layer and atleast one of insulating layers constituting the blocking insulatinglayer may have a larger dielectric constant than the tunnel insulatinglayer.

In yet further example embodiments, the tunnel insulating layer mayinclude at least one silicon oxide layer; the charge storing layer mayinclude one of insulating layers having a higher density of a trap sitethan a silicon oxide layer and insulating layers having intrinsicconductive nano particles and the blocking insulating layer may includeat least one of an aluminum oxide layer, a hafnium oxide layer, azirconium oxide layer, a tantalum oxide layer, a titanium oxide layer, asilicon nitride layer, a silicon oxynitride layer, or a silicon oxidelayer. In yet further example embodiments, the electrodes may include atleast one of doped silicon, metal materials, metal nitrides, or metalsilicides. In yet further example embodiments, the electrodes may beformed of a conductive material having a lower resistivity than dopedsilicon.

In yet further example embodiments, the semiconductor pattern mayinclude a spacer portion to be inserted in the first pattern and a bodyportion to be inserted in the semiconductor spacer, a bottom surface ofthe body portion being lower than that of the spacer portion. In yetfurther example embodiments, the body portion directly may contact thesubstrate and the spacer portion may be spaced from the substrate. Inyet further embodiments, the body portion may include a core regioncovering an inner wall of the semiconductor spacer and a connectionregion extending from the core region to be inserted into a top surfaceof the substrate. In yet further example embodiments, a connectionregion of the body portion may extend horizontally to have a broaderwidth than the spacer portion.

In yet further example embodiments, a connection region of the bodyportion may pass below the memory element to directly contact an innersidewall of the substrate, thereby covering a bottom surface of thefirst pattern. In yet further example embodiments, the substrate may beformed of a semiconductor material having less crystal defects than thebody portion. In yet further example embodiments, the spacer portion mayprotrude downwardly compared to a bottom surface of the first pattern.In yet further example embodiments, the three-dimensional semiconductordevices may further include a selection structure interposed between theelectrode structure and the substrate, the selection structure includingselection lines and a selection active pattern penetrating the selectionlines to connect the semiconductor pattern with the substrate. A bottomsurface of the first pattern is formed above the uppermost surface ofthe selection lines.

In yet further example embodiments, the first pattern may include acharge storing layer, a tunnel insulating layer between the chargestoring layer and the semiconductor pattern, and a capping layer betweenthe charge storing layer and the electrode, the charge storing layerprotruding more downward than the capping layer and the tunnelinsulating layer and a bottom surface of the capping layer being formedmore adjacent to a top surface of the substrate than a bottom surface ofthe tunnel insulating layer. In yet further example embodiments, thesubstrate may include a contact region contacting the semiconductorpattern and a source region spaced from the contact region, the contactregion having the same conductive type as the semiconductor pattern andthe source region having a different conductive type than the contactregion. In yet further example embodiments, the three-dimensionalsemiconductor devices may further include a source conductive patternpenetrating the electrode structure to contact the source region.

According to other example embodiments of the inventive concepts,methods of fabricating a three-dimensional semiconductor device mayinclude forming a mold structure on a substrate, the mold structureincluding sequentially and alternately stacked mold layers andsacrificial layers, forming an opening penetrating the mold structure,forming a first pattern and a semiconductor pattern covering an innerwall of the opening sequentially, forming recess regions between themold layers by removing the sacrificial layers and forming a secondpattern and an electrode covering an inner wall of the recess regionsequentially.

In some example embodiments, the forming of the first pattern mayinclude forming a tunnel insulating layer and the forming of the secondpattern may include sequentially forming a charge storing layer and ablocking insulating layer. The tunnel insulating layer and the blockinginsulating layer may be formed of a material having a larger band gapthan the charge storing layer and the blocking insulating layer may beformed of a material having a larger dielectric constant than the tunnelinsulating layer. In other example embodiments, the forming of the firstpattern may include forming a charge storing layer and a tunnelinsulating layer sequentially and the forming of the second pattern mayinclude forming a blocking insulating layer. The tunnel insulating layerand the blocking insulating layer may be formed of a material having alarger band gap than the charge storing layer and the blockinginsulating layer being formed of a material having a larger dielectricconstant than the tunnel insulating layer.

In still other example embodiments, the tunnel insulating layer may beformed after the forming of the charge storing layer and the blockinginsulating layer may be formed after the forming of the charge storinglayer. In even other example embodiments, the forming of the firstpattern may include forming a capping layer before the forming of thecharge storing layer, the capping layer being formed of a differentmaterial than the charge storing layer. In yet other exampleembodiments, the forming of the recess region may include isotropicallyetching the sacrificial layer by using an etch recipe having an etchselectivity with respect to the mold layer and the capping layer. Infurther example embodiments, the method may further include, before theforming of the second pattern, exposing an outer wall of the firstpattern by etching the capping layer exposed by the recess region. Instill further example embodiments, by substantially forming the secondpattern and the first pattern with a material having the same chemicalcomposition, two kinds of atoms having the highest content of the secondpattern may be identical to those having the highest content of thefirst pattern.

In even further example embodiments, the forming of the first patternand the semiconductor pattern may include forming a first layer and afirst semiconductor layer covering an inner wall of the openingsequentially, forming a first semiconductor pattern exposing the firstlayer at a bottom of the opening by isotropically etching the firstsemiconductor layer, and isotropically etching the first layer by usingthe first semiconductor pattern as an etch mask. In yet further exampleembodiments, the methods may further include, before the isotropicallyetching of the first layer, opening again a bottom surface of theopening by anisotropically etching the first layer by using the firstsemiconductor pattern as an etch mask. In yet further exampleembodiments, the methods may further include, before the forming of themold layer, forming a selection active pattern connecting thesemiconductor pattern with the substrate.

According to still other example embodiments of the inventive concepts,three-dimensional semiconductor devices include an electrode structureincluding electrodes stacked sequentially on a substrate, interlayerinsulating layers interposed between the electrodes at a verticalposition, a semiconductor pattern penetrating the electrode structure, asecond pattern interposed between the electrode and the semiconductorpattern and between the electrode and the interlayer insulating layer,and a first pattern interposed in a region between the semiconductorpattern and the interlayer insulating layer. The second pattern and thefirst second pattern are substantially the same in terms of at least oneof a chemical composition or an electrical property. In some exampleembodiments, the first pattern vertically may extend to be interposed ina region between sidewalls of the second pattern and the semiconductorpattern. In other example embodiments, two kinds of atoms having thehighest content of the second pattern may be identical to those havingthe highest content of the first pattern.

According to even other example embodiments of the inventive concepts,three-dimensional semiconductor devices include a selection structureand a memory structure stacked sequentially on a semiconductorsubstrate. The selection structure includes selection lines, a selectionactive pattern, and a selection gate insulating layer, the selectionactive pattern penetrating the selection lines to contact thesemiconductor substrate, the selection gate insulating layer beingdisposed between the selection lines and the selection active pattern.The memory structure includes word lines, a memory active pattern, and amemory gate insulating layer, the memory active pattern penetrating theword lines to contact the selection active pattern, the memory gateinsulating layer being disposed between the word lines and the memoryactive pattern, and a portion of the memory gate insulating layerextending to cover a top surface and a bottom surface of the word line.

In some example embodiments, a bottom region of the selection activepattern may be inserted at a predetermined depth in a top surface of thesemiconductor substrate, with the selection gate insulating layer beinglocally formed between the selection active pattern and sidewalls of theselection line so that an inserted portion of the selection activepattern all directly contacts the semiconductor substrate. In otherexample embodiments, the semiconductor substrate may include a recessregion into which the selection active pattern is inserted and a widthof the recess region of the semiconductor substrate may be identical tothat of the selection active pattern inserted into the recess region. Instill other example embodiments, the selection active pattern may beformed of a semiconductor having the same conductive type as a region ofthe semiconductor substrate that the selection active pattern contactsor an intrinsic semiconductor, and the selection active pattern may beformed of a semiconductor having the same conductive type as the memoryactive pattern.

In even other example embodiments, the selection active pattern mayinclude a sidewall penetrating the selection lines and a bottomextending horizontally and continuously from a bottom region of thesidewall to cover a top surface of the semiconductor substrate. Ahorizontal thickness of the sidewall may be substantially formed withthe same thickness as a vertical thickness of the bottom so that theselection active pattern has a U-shaped section. In yet other exampleembodiments, the selection active pattern may have a rectangular ortrapezoidal section at least below the lowest bottom surface of thememory active pattern. In further example embodiments, the memory gateinsulating layer may include a blocking insulating layer adjacent to theword line, a tunnel insulating layer adjacent to the memory activepattern, and a charge storing layer interposed between the blockinginsulating layer and the tunnel insulating layer, with the selectiongate insulating layer being different from the memory gate insulatinglayer in terms of at least one of material or thickness.

In still further example embodiments, the selection gate insulatinglayer may be substantially identical to the blocking insulating layer interms of at least one of material or thickness. In even further exampleembodiments, the tunnel insulating layer may cross over a plurality ofvertically-stacked word lines and the blocking insulating layer maycross over a plurality of horizontally-arranged memory active patterns.In yet further example embodiments, the selection active pattern may beformed of silicon and the selection gate insulating layer may be asilicon oxide layer formed in a local region between the selectionactive pattern and the selection line. The selection active patternbeing thicker on or below the selection line than around the selectiongate insulating layer.

According to yet other example embodiments of the inventive concepts,methods of fabricating three-dimensional structure devices may includeforming a mold structure on a substrate, forming an opening penetratingthe mold structure to recess a top surface of the substrate at apredetermined depth, sequentially forming a first layer and a firstsemiconductor layer to cover an inner wall of the opening, forming apenetrating dent penetrating the first semiconductor layer and the firstlayer at a bottom of the opening to again expose a top surface of thesubstrate, forming an under-cut region exposing a sidewall of thesubstrate recessed by the opening by isotropically etching the firstlayer exposed through the penetrating dent, and forming a secondsemiconductor layer in the under-cut region to connect the substrate andthe first semiconductor layer.

In some example embodiments, the first layer and the first semiconductorlayer may be sequentially formed to substantially cover an inner wall ofthe opening with a conformal thickness, and the sum of depositionthicknesses of the first layer and the first semiconductor layer may beless than the half of a width of the opening. The forming of thepenetrating dent may include forming a semiconductor spacer to expose atop surface of the first layer at a bottom of the opening byanisotropically etching the first semiconductor layer andanisotropically etching the first layer exposed by the semiconductorspacer.

In other example embodiments, the forming of the penetrating dent mayfurther include, before the anisotropically etching of the firstsemiconductor layer, forming a protective layer spacer to expose abottom surface of the first semiconductor layer in an inner sidewall ofthe first semiconductor layer, and the protective layer spacer may beformed of a material having an etch selectivity with respect to thefirst semiconductor layer and may be formed with a thinner thicknessthan the half of a difference between the half of a width of the openingand the sum of deposition thicknesses of the first layer and the firstsemiconductor layer. In still other example embodiments, the methods mayfurther include, before the forming of the under-cut region,isotropically etching the first semiconductor layer by using theprotective layer spacer as an etch mask.

In even other example embodiments, the protective layer spacer may beremoved during the forming of the under-cut region. In yet other exampleembodiments, the first layer may include a capping layer, a chargestoring layer, and a tunnel layer, which sequentially cover an innerwall of the opening. The forming of the under-cut region may includeforming a first under-cut region to expose the capping layer and thetunnel layer by isotropically etching the charge storing layer exposedby the penetrating dent, and forming a second under-cut region byisotropically etching the capping layer and the tunnel layer exposed bythe first under-cut region. In further example embodiments, the firstlayer may include a capping layer, a charge storing layer, and a tunnellayer, which sequentially cover an inner wall of the opening. Theforming of the under-cut region may include forming a first under-cutregion to expose the charge storing layer by isotropically etching thetunnel layer and the capping layer exposed by the penetrating dent andforming a second under-cut region by isotropically etching the chargestoring layer exposed by the first under-cut region.

According to further example embodiments of the inventive concepts,methods of fabricating three-dimensional structure devices includeforming a multi-layered structure on a substrate, forming an openingpenetrating the multi-layered structure to recess a top surface of thesubstrate at a predetermined depth, sequentially forming a first layerand a first semiconductor layer to cover an inner wall of the opening,forming a protective layer spacer in an inner sidewall of the firstsemiconductor layer to expose a bottom surface of the firstsemiconductor layer, forming an under-cut region to expose a sidewall ofthe substrate recessed by the opening by sequentially and isotropicallyetching the first semiconductor layer and the first layer using theprotective layer spacer as an etch mask, and forming a secondsemiconductor layer in the under-cut region to connect the substratewith the first semiconductor layer.

In some example embodiments, the isotropically etching of the firstsemiconductor layer may include exposing a surface of the first layer bydry-etching an exposed surface of the first semiconductor layer, thedry-etching being performed at atmosphere withoutintentionally-generated plasma. In other example embodiments, thedry-etching may be performed using (1) first gas including fluorineatoms, (2) second gas including chlorine atoms, and/or (3) carrier gasincluding at least one of argon, helium or nitrogen. In still otherexample embodiments, the dry-etching may be performed under a pressurecondition of less than 1 atmospheric pressure and a temperaturecondition of about 350° C. to about 500° C. In even other exampleembodiments, the isotropically etching of the first layer may includeetching a surface of the first layer by using an etchant, the surface ofthe first layer being exposed by etching the first semiconductor layer.

In yet other example embodiments, the etchant may include liquidmaterials having an etch selectivity with respect to the firstsemiconductor layer and used for etching the first layer. In furtherexample embodiments, the first layer may include a plurality of thinlayers covering an inner wall of the opening and at least one of thethin layers constituting the first layer is a silicon oxide layer or asilicon nitride layer. In still further example embodiments, the firstlayer may include a capping layer, a charge storing layer, and a tunnelinsulating layer, which sequentially cover an inner wall of the openingand the isotropically etching of the first layer includes sequentiallyand isotropically etching the tunnel insulating layer, the chargestoring layer, and the capping layer. The etching of the tunnelinsulating layer and the capping layer is performed using an etchantincluding fluorine acid and the etching of the charge storing layer isperformed using an etchant including phosphoric acid. In even furtherexample embodiments, the protective layer spacer may be etched andremoved during the isotropically etching of the first layer.

According to one or more example embodiments, a three-dimensionalsemiconductor device includes an electrode structure including a stackedplurality of electrodes on a substrate, a plurality of semiconductorpatterns penetrating the electrode structure and a plurality of memoryelements between the semiconductor patterns and the electrode structure,the memory elements including a first pattern extending in a firstdirection to cross the plurality of electrodes and a second patternextending in a second direction orthogonal to the first direction tocross the plurality of semiconductor patterns.

According to one or more example embodiments, a three-dimensionalsemiconductor device includes an electrode structure including aplurality of electrodes stacked sequentially on a substrate, a pluralityof interlayer insulating layers between the plurality of electrodes,respectively, a semiconductor pattern penetrating the electrodestructure, a first pattern between the electrodes and the semiconductorpattern and between the electrodes and the interlayer insulating layers,and a second pattern between the semiconductor pattern and theinterlayer insulating layer, at least one of a chemical composition andan electrical property of the first pattern substantially identical to acorresponding one of a chemical composition and an electrical propertyof the second pattern.

According to one or more example embodiments, a three-dimensionalsemiconductor device includes a selection structure on a semiconductorsubstrate, the selection structure including a plurality of selectionlines, a selection active pattern, and a selection gate insulatinglayer, the selection active pattern penetrating the selection lines tocontact the semiconductor substrate, the selection gate insulating layerbetween the selection lines and the selection active pattern, and amemory structure stacked on the selection structure, the memorystructure including a plurality of word lines, a memory active pattern,and a memory gate insulating layer, the memory active patternpenetrating the word lines to contact the selection active pattern, thememory gate insulating layer between the word lines and the memoryactive pattern, at least a portion of the memory gate insulating layercovering at least a portion of opposing surfaces of each of the wordlines.

According to one or more example embodiments, a method of fabricating athree-dimensional semiconductor device includes forming a mold structureincluding a plurality of mold layers alternately stacked with aplurality of sacrificial layers on a substrate, forming an openingpenetrating the mold structure, sequentially forming a first pattern anda semiconductor pattern on an inner wall of the mold structure insidethe opening, forming recess regions between the mold layers by removingthe sacrificial layers, and sequentially forming a second pattern and anelectrode between the mold layers in the recess region.

According to one or more example embodiments, a method of fabricating athree-dimensional semiconductor device includes forming a mold structureon a substrate, forming an opening penetrating through the moldstructure and a surface of the substrate so that a recess is formed inthe substrate, sequentially forming a first layer and a firstsemiconductor layer to cover an inner wall of the mold structure in theopening and the substrate in the recess, forming a penetrating dent topenetrate through the first semiconductor layer and the first layer toexpose a surface of the substrate in the recess, forming an under-cutregion exposing a sidewall of the substrate in the recess byisotropically etching the first layer exposed by the penetrating dent,and forming a second semiconductor layer in the under-cut region toconnect the substrate and the first semiconductor layer.

According to one or more example embodiments, a method of fabricating athree-dimensional semiconductor device includes forming a multi-layeredstructure on a substrate, forming an opening penetrating themulti-layered structure and recessing a surface of the substrate,sequentially forming a first layer and a first semiconductor layer tocover an inner wall of the multi-layered structure and the recessedsubstrate in the opening, forming a protective layer spacer on an innersidewall of the first semiconductor layer, forming an under-cut regionto expose a sidewall of the recessed substrate in the opening bysequentially and isotropically etching the first semiconductor layer andthe first layer using the protective layer spacer as an etch mask, andforming a second semiconductor layer in the under-cut region to connectthe substrate with the first semiconductor layer.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will be more clearly understood from the followingbrief description taken in conjunction with the accompanying drawings.FIGS. 1-93 represent non-limiting, example embodiments as describedherein.

FIGS. 1-11 are perspective views illustrating methods of fabricatingthree-dimensional semiconductor devices according to example embodimentsof the inventive concepts;

FIGS. 12-21 are perspective views illustrating methods of fabricatingthree-dimensional semiconductor devices according to example embodimentsof the inventive concepts;

FIGS. 22-24 are perspective views illustrating three-dimensionalsemiconductor devices fabricated according to example embodiments of theinventive concepts described with respect to FIGS. 1-11 ;

FIGS. 25-27 are perspective views illustrating three-dimensionalsemiconductor devices fabricated according to example embodiments of theinventive concepts described with respect to FIGS. 22-24 ;

FIGS. 28-43 are perspective views illustrating structures of informationstoring layers according to example embodiments of the inventiveconcepts;

FIGS. 44-46 are cross-sectional diagrams illustrating three-dimensionalsemiconductor devices according to example embodiments;

FIGS. 47 and 48 are perspective views illustrating three-dimensionalsemiconductor devices according to example embodiments;

FIGS. 49-54 are cross-sectional diagrams illustrating crossingstructures according to example embodiments of the inventive concepts;

FIGS. 55 and 56 are perspective views illustrating crossing structuresaccording to example embodiments of the inventive concepts;

FIGS. 57-66 are cross-sectional diagrams illustrating methods offabricating the three-dimensional semiconductor devices described withreference to FIG. 46 and other example embodiments;

FIG. 67 is a cross-sectional diagram illustrating example embodimentsdescribed with reference to FIG. 64 ;

FIGS. 68 and 69 are cross-sectional diagrams to comparethree-dimensional semiconductor devices according to example embodimentsof the inventive concepts;

FIGS. 70-82 are cross-sectional diagrams illustrating methods offabricating undercut regions according to example embodiments of theinventive concepts;

FIG. 83 is a cross-sectional diagram illustrating a current path in athree dimensional semiconductor device described with reference to FIGS.70-82 ;

FIGS. 84-90 are cross-sectional diagrams illustrating methods offabricating undercut regions according to example embodiments of theinventive concepts;

FIG. 91 is a cross-sectional diagram illustrating a current path in athree-dimensional semiconductor device described with reference to FIGS.84-90 ;

FIG. 92 is a block diagram illustrating memory cards equipped with flashmemory devices according to example embodiments of the inventiveconcepts; and

FIG. 93 is a block diagram illustrating information processing systemsincluding memory systems according to example embodiments of theinventive concepts.

It should be noted that these figures are intended to illustrate thegeneral characteristics of methods, structure and/or materials utilizedin certain example embodiments and to supplement the written descriptionprovided below. These drawings are not, however, to scale and may notprecisely reflect the precise structural or performance characteristicsof any given embodiment, and should not be interpreted as defining orlimiting the range of values or properties encompassed by exampleembodiments. For example, the relative thicknesses and positioning ofmolecules, layers, regions and/or structural elements may be reduced orexaggerated for clarity. The use of similar or identical referencenumbers in the various drawings is intended to indicate the presence ofa similar or identical element or feature.

DETAILED DESCRIPTION

Example embodiments of the inventive concepts will now be described morefully with reference to the accompanying drawings, in which exampleembodiments are shown. Example embodiments of the inventive conceptsmay, however, be embodied in many different forms and should not beconstrued as being limited to the embodiments set forth herein; rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the concept of example embodimentsto those of ordinary skill in the art. In the drawings, the thicknessesof layers and regions are exaggerated for clarity. Like referencenumerals in the drawings denote like elements, and thus theirdescription will be omitted.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. Like numbers indicate like elementsthroughout. As used herein the term “and/or” includes any and allcombinations of one or more of the associated listed items. Other wordsused to describe the relationship between elements or layers should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” “on” versus “directlyon”).

It will be understood that, although the terms “first”, “second”, etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer orsection from another element, component, region, layer or section. Thus,a first element, component, region, layer or section discussed belowcould be termed a second element, component, region, layer or sectionwithout departing from the teachings of example embodiments.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of exampleembodiments. As used herein, the singular forms “a,” “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises”, “comprising”, “includes” and/or “including,” if usedherein, specify the presence of stated features, integers, steps,operations, elements and/or components, but do not preclude the presenceor addition of one or more other features, integers, steps, operations,elements, components and/or groups thereof.

Example embodiments of the inventive concepts are described herein withreference to cross-sectional illustrations that are schematicillustrations of idealized embodiments (and intermediate structures) ofexample embodiments. As such, variations from the shapes of theillustrations as a result, for example, of manufacturing techniquesand/or tolerances, are to be expected. Thus, example embodiments of theinventive concepts should not be construed as limited to the particularshapes of regions illustrated herein but are to include deviations inshapes that result, for example, from manufacturing. For example, animplanted region illustrated as a rectangle may have rounded or curvedfeatures and/or a gradient of implant concentration at its edges ratherthan a binary change from implanted to non-implanted region. Likewise, aburied region formed by implantation may result in some implantation inthe region between the buried region and the surface through which theimplantation takes place. Thus, the regions illustrated in the figuresare schematic in nature and their shapes are not intended to illustratethe actual shape of a region of a device and are not intended to limitthe scope of example embodiments.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which example embodiments of theinventive concepts belong. It will be further understood that terms,such as those defined in commonly-used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and will not be interpreted in anidealized or overly formal sense unless expressly so defined herein.

A three-dimensional semiconductor device according to exampleembodiments of the inventive concepts may include a cell array region, aperipheral circuit region, a sense amp region, a decoding circuit regionand a connection region. A plurality of memory cells and bit lines andword lines for electrical connection to the plurality of memory cellsmay be in the cell array region. Circuits for driving the plurality ofmemory cells may be in the peripheral circuit region, and circuits forreading information stored in the plurality of memory cells may be inthe sense amp region. The connection region may be between the cellsarray region and the decoding circuit region, and a wiring structure forelectrically connecting the word lines with the decoding circuit regionmay be between the word lines and the decoding region.

Hereinafter, technical features related partially to a cell array regionof a three-dimensional device will be mainly described. In addition,Korean Patent Application Nos. 2009-0126854, filed on Dec. 18, 2009,2010-0014751, filed on Feb. 18, 2010, 2010-0006124, filed on Jan. 22,2010, and 2009-0099370, filed on Oct. 19, 2009, and U.S. patentapplication Ser. No. 12/480,399, filed on Jun. 8, 2009, may disclosetechnical features related to the cell array region and other regions(e.g., a peripheral region or a connection region). The entire contentsdisclosed in Korean Patent Application Nos. 2009-0126854, 2010-0014751,2010-0006124 and 2009-0099370, and U.S. patent application Ser. No.12/480,399 are hereby incorporated as part of this application.

Furthermore, Korean Patent Application No. 2010-0006124, the disclosureof which is incorporated by reference herein in its entirety, maydisclose a multi-layered memory structure obtained by repeatedly forminga memory structure. That is, in some embodiments of the inventiveconcept, a multilayered memory structure may be formed by repeatedlystacking a memory structure, which will be explained in the followingdescription, using ways disclosed in the Korean Patent Application No.2010-0006124.

FIGS. 1-11 are perspective views illustrating methods of fabricatingthree-dimensional semiconductor devices according to example embodimentsof the inventive concepts. Referring to FIG. 1 , a mold structure 100may be formed on a substrate 10. The substrate 10 may be, for example, amaterial having semiconductor property, an insulation material, asemiconductor, a conductor, and/or one or more of these materialscovered by an insulation material. For example, the substrate 10 may bea silicon wafer. According to example embodiments, a substrate mayinclude one or more layers supported by another layer and/or structure.For example, a semiconductor substrate may include a semiconductor layeron a material having semiconductor property, an insulation material, asemiconductor, a conductor, and/or one or more of these materialscovered by an insulation material.

According to example embodiments, a bottom structure (not shown)including at least one transistor may be disposed between the substrate10 and the mold structure 100. In the following description, for easierunderstanding of example embodiments of the inventive concepts, exampleembodiments may be described with a mold structure 100 directly formedon a substrate 10. However, example embodiments of the inventiveconcepts are not limited thereto.

The mold structure 100 may include an insulating layer group 120including a plurality of insulating layers (e.g., insulating layers121-129) and a sacrificial layer group 130 including a plurality ofsacrificial layers (e.g., sacrificial layers 131-138). The insulatinglayers 121-129 and the sacrificial layers 131-138 may be stacked in analternating. The sacrificial layer group 130 may include at least onematerial with an etch selectivity to the insulating layer group 120. Theinsulating layer group 120 may include a material that is etched at aslower rate than a material of the sacrificial layer group 130 withrespect to a sacrificial layer material etchant.

The etch selectivity may be quantitatively expressed as a ratio of anetch speed of a material of the sacrificial layer group 130 to amaterial of the insulating layer group 120. According to exampleembodiments, the sacrificial layer 130 may be one or more materialsproviding an etch selectivity of 1:10 to 1:200 (e.g., 1:30 to 1:100)with respect to one or more materials of the insulating layer group 120.For example, the insulating layer group 120 may be at least one of asilicon oxide and a silicon nitride, and the sacrificial layer group 130may be at least one of silicon, a silicon oxide, a silicon carbide andsilicon nitride. The sacrificial layer group 130 may be selected to be adifferent material from the insulating layer group 120. In the followingdescription, for easier understanding of example embodiments of theinventive concepts, example embodiments will be described with respectto a silicon oxide insulating layer group 120 and a silicon nitridesacrificial layer group 130. However, example embodiments are notlimited to silicon oxide and silicon nitride, and each layer group isnot limited to a single material.

According to example embodiments, the sacrificial layers 131-138 may beformed to substantially the same thickness. Thicknesses of theinsulating layers 121-129 may not be substantially the same. Forexample, in the insulating layer group 120, the insulating layer 121 maybe thinner than each of the sacrificial layers 131-138. The insulatinglayer 123 and the insulating layer 128 may be thicker than each of thesacrificial layers 131-138. Each of the insulating layers 122, 124-127and 129 of the insulating layer group 120 may be thicker, thinner orsubstantially a same thickness as any of the sacrificial layers 131-138.However, the thicknesses of the insulating layers 121-129 may bemodified from the drawings and the number of layers constituting themold structure 100 may be diversely modified.

Hereinafter, for ease of explanation, each insulating layer 121-129 ofthe insulating layer group 120 will be described and depicted in thedrawings as an insulating layer 120 and each sacrificial layer 131-138of the sacrificial layer group 130 will be described and depicted as asacrificial layer 130.

Referring to FIGS. 2 and 3 , openings 105 may be formed to penetrate themold structure 100. A vertical layer 150 may be formed to conformallycover the inner walls of the openings 105. The vertical layer 150 mayextend horizontally from the openings 105 to cover the top surface ofthe mold structure 100. According to example embodiments, the openings105 may be formed with, for example, a hole shape. Each of the openings105 may be formed with a shape in which its depth may be at least fivetimes its width (e.g., an aspect ratio of 5). According to exampleembodiments, the openings 105 may be two-dimensionally formed on the topsurface (i.e., the xy plane) of the substrate 10. For example, eachopening 105 may be an isolated region spaced apart from other openings105 along x and y directions.

The forming of the openings 105 may include forming a mask patterndefining positions of the openings 105 on the mold structure 100 and,for example, anisotropically etching the mold structure 100 using themask pattern as an etch mask. Because the mold structure 100 may includetwo kinds of different layers, the sidewall of the opening 105 may notbe completely uniform from the top surface of the substrate 10. Forexample, as the opening 105 is closer to the top surface of thesubstrate 10 the width of the opening 105 may be reduced. Thisnon-uniform width of the opening 105 may cause non-uniformity inoperational characteristics of three-dimensionally arranged transistors.Detailed description of this non-uniformity and methods of improving thesame may be disclosed in U.S. patent application Ser. No. 12/420,518,the entire contents of which are incorporated as part of thisapplication.

A mold structure 100 may be directly formed on the substrate 10. Theopening 105 may be formed to expose the top surface of the substrate 10as illustrated. The substrate 10 below the opening 105 may be recesseddue to over-etch during the anisotropic etching of the mold structure100. The vertical layer 150 may include one thin layer or a plurality ofthin layers. For example, the vertical layer 150 may include at leastone of thin layers used as a memory element of a charge trap typenonvolatile memory transistor. Example embodiments of the inventiveconcepts may be diversely classified according to the thin layers of thevertical layer 150.

Referring to FIG. 4 , a vertical pattern 155 and a semiconductor spacer165 may be formed on each inner wall of the openings 105. The forming ofthe vertical pattern 155 and a semiconductor spacer 165 may includeforming a first semiconductor layer (not shown) that conformally coversthe hole 105 with the vertical layer 150, and anisotropically etchingthe first semiconductor layer and the vertical layer 150 to expose thetop surface of the substrate 10 at the bottom of the openings 105. Thevertical pattern 155 and the semiconductor spacer 165 may be formedwith, for example, a cylindrical shape with open ends. The top surfaceof the substrate 10 exposed by the semiconductor spacer 165 may berecessed by over etching during the anisotropic etching of the firstsemiconductor layer.

During the anisotropic etching of the first semiconductor layer and thevertical layer 150, the vertical layer 150 under the semiconductorspacer 165 may not be fully etched, and the vertical pattern 155 mayinclude a bottom portion between the bottom surface of the semiconductorspacer 165 and the top surface of the substrate 10. Example embodimentsmay include etching the exposed surface of the vertical pattern 155using the semiconductor spacer 165 as an etch mask. As illustrated inFIG. 24 , an under-cut region may be formed below the semiconductorspacer 165 and the length of the vertical pattern 155 may be shorterthan that of the semiconductor spacer 165.

The top surface of the mold structure 100 may be exposed by theanisotropic etching of the first semiconductor layer and the verticallayer 150. Each of the vertical patterns 155 and the semiconductorspacers 165 may be localized in the openings 105. The vertical patterns155 and the semiconductor spacers 165 may be two-dimensionally arrangedon the xy plane.

The first semiconductor layer may be a silicon layer (e.g., apolycrystalline silicon layer) formed using one of, for example, atomiclayer deposition (ALD) and chemical vapor deposition (CVD). The firstsemiconductor layer may be formed, for example, with a thickness rangingfrom about 1/50 to ⅕ of the width of the opening 105. The firstsemiconductor layer may be formed using an epitaxial technique. KoreanPatent Application No. 2010-0009628, filed on Feb. 2, 2010, thedisclosure of which is incorporated by reference herein in its entirety,may disclose epitaxial techniques. According to example embodiments ofthe inventive concepts, the first semiconductor layer may be, forexample, one of an organic semiconductor layer and carbon nanostructures.

Referring to FIGS. 5 and 6 , a second semiconductor layer 170 and aburied insulating layer 180 may be formed on the structure including thevertical pattern 155 (e.g., sequentially deposited). The secondsemiconductor layer 170 may be a silicon layer (e.g., a polycrystallinesilicon layer) formed using, for example, ALD and/or CVD. According toexample embodiments, the second semiconductor layer 170 may beconformally formed to a thickness that does not completely bury theopening 105. The second semiconductor layer 170 may define a hole 105 ain the opening 105.

The buried insulating layer 180 may be formed to fill the hole 105 a andmay an insulation material formed by, for example, using spin-on-glass(SOG) and/or forming a silicon oxide layer. According to exampleembodiments a hydrogen annealing step for thermally treating thestructure including the second semiconductor layer 170 under a gasatmosphere including hydrogen and/or heavy hydrogen may be performed(e.g., before the forming of the buried insulating layer 180). Crystaldefects in the semiconductor spacer 165 and the second semiconductorlayer 170 may be cured and/or reduced during the hydrogen annealing.

According to example embodiments of the inventive concepts, the secondsemiconductor layer 170 may be formed to fill the openings 105 in whichthe semiconductor spacers 165 are formed, and the forming of the buriedinsulating layer 180 may be omitted as illustrated in FIGS. 23 and 24 .Referring to FIG. 7 , trenches 200 penetrating the mold structure 100and exposing the sidewalls of the sacrificial layers 130 and theinsulating layers 120 may be formed. The trenches 200 may be spacedapart from and cross over between the openings 105.

The forming of the trenches 200 may include forming an etch mask on themold structure 100 and/or on the buried insulating layer 180 andanisotropically etching layers below the etch mask to, for example,expose the top surface of the substrate 10. The second semiconductorlayer 170 and the buried insulating layer 180 may be patterned to definetop entrances of the trenches 200 above the mold structure 100. Thesubstrate 10 under the trench 200 may be recessed by over-etching duringanisotropic etching of the layers below the etch mask. Because theopening 105 and the trenches 200 may be formed by etching the samelayers, similar to the opening 105, the closer to the top surface of thesubstrate 10, the narrower the trench may be (e.g., may have a reducedwidth). This non-uniform width of the trench 200 may causenon-uniformity in operational characteristics of three-dimensionallyarranged transistors. Detailed description of this non-uniformity andimproving methods thereof may be disclosed in U.S. patent applicationSer. No. 12/420,518, the entire contents of which are incorporated aspart of this application.

According to example embodiments, a pair of trenches 200 may be formedat both sides of each of the openings 105. The number of the openings105 with the same y coordinate and arranged along the x-axis may besubstantially equal to that of the trenches 200. However, exampleembodiments of the inventive concepts are not limited thereto and thenumber of openings with the same y coordinate and arranged along thex-axis may be different than the number of trenches. For example, KoreanPatent Application No. 2009-0126854, filed on Dec. 18, 2009, disclosesembodiments related to a relative arrangement of trenches with respectto openings, the entire contents of which is hereby incorporated as partof this application.

Referring to FIG. 8 , recess regions 210 may be formed between theinsulating layers 120 by selectively removing the exposed sacrificiallayers 130. The recess regions 210 may be gap regions extendinglaterally from the trenches 200, and may be formed to expose thesidewalls of the vertical patterns 155. An outer boundary of the recessregion 210 may be defined by the insulating layers 120 and the trenches200 at both sides of the outer boundary. An internal boundary of therecess region 210 may be defined by the vertical patterns 155 verticallypenetrating the internal boundary. The forming of the recess regions 210may include horizontally etching the sacrificial layers 130 using, forexample, an etchant and/or etch process with etch selectivity to theinsulating layers 120 and the vertical patterns 155. For example, if thesacrificial layers 130 are silicon nitride layers and the insulatinglayers 120 are silicon oxide layers, the horizontal etch may beperformed using an etchant including phosphoric acid.

Referring to FIG. 9 , horizontal structures HS filling the recessregions 210 are formed. The horizontal structure HS may includehorizontal patterns 220 covering the inner walls of the recess region210 and a conductive pattern 230 filling the remaining space. Theforming of the horizontal structures HS may include forming a horizontallayer and a conductive layer (not shown) to fill the recess regions 210(e.g., sequentially forming), and removing the conductive layer in thetrenches 200 so that the conductive patterns 230 remain in the recessregions 210. The horizontal layer or the horizontal pattern 220 may beone thin layer and/or a plurality of thin layers (e.g., similarly to thevertical layer 150). According to example embodiments, the horizontalpattern 220 may include a blocking dielectric layer of a charge traptype nonvolatile memory transistor. Example embodiments of the inventiveconcepts may be diversely classified according to the thin layers usedas the vertical layer 150 and the horizontal pattern 220.

The conductive layer may be formed to fill the recess regions 210covered by the horizontal layer. The trenches 200 may be completelyand/or partially filled by the conductive layer. The conductive layermay include, for example, doped silicon, metallic materials, metalnitride layers, and/or metal silicide. For example, the conductive layermay include a tantalum nitride layer and/or tungsten. According toexample embodiments, the conductive layer may be formed to conformallycover the inner walls of the trench 200, and the forming of theconductive pattern 230 may include removing the conductive layer in thetrench 200 using, for example, an isotropic etch. According to exampleembodiments, the conductive layer may be formed to fill the trench 200and the forming of the conductive pattern 230 may include, for example,an isotropic etch of the conductive layer in the trench 200.

According to example embodiments of the inventive concepts with respectto a flash memory, impurity regions 240 may be formed. The impurityregions 240 may be formed through an ion implantation process, and maybe formed in the substrate 10 exposed through the trench 200. Theimpurity regions 240 may be a different conductive type than thesubstrate 10. A region (hereinafter, a contact region) of the substrate10 contacting the second semiconductor layer 170 may be the sameconductive type as the substrate 10. The impurity regions 240 and thesubstrate 10 and/or the second semiconductor layer 170 may form a P-Njunction. According to example embodiments, the impurity regions 240 maybe connected to each other and may be in an equipotential state.According to example embodiments, the impurity regions 240 may be atdifferent electric potentials and may be electrically separated fromeach other. According to example embodiments, the impurity regions 240may be a plurality of separate source groups including differentimpurity regions and the source groups may be electrically separatedfrom each other to be at different electric potentials.

Referring to FIG. 10 , an electrode separation pattern 250 may be formedto fill the trenches 200. The forming of the electrode separationpattern 250 may include forming an electrode separation layer (notshown) on the structure including the impurity regions 240 and etchingto expose the top surface of the mold structure 100. The electrodeseparation layer may be formed of, for example, at least one of asilicon oxide layer, a silicon nitride layer and a silicon oxynitridelayer. The etch step may be performed using a planarization technique,for example, a chemical-mechanical polishing technique and/or anetch-back technique. The buried insulating layer 180 and the secondsemiconductor layer 170 may form buried patterns 185 and semiconductorbody portions 175 in each of the openings 105.

According to example embodiments of the inventive concepts, a pluralityof vertical structures VS penetrating the mold structure 100 may betwo-dimensionally formed on the substrate 10. Each of the verticalstructures VS may include the vertical pattern 155, the semiconductorspacer 165, the semiconductor body portion 175 and/or the buriedpatterns 185. Positions of the vertical structures VS may be defined bythe openings 105.

Referring to FIG. 11 , upper plugs 260 may be formed on each of thevertical structures VS and upper wirings 270 may be formed on the upperplugs 260 to connect the vertical structures VS and upper wirings 270.According to example embodiments, the top regions of the semiconductorspacer 165 and the semiconductor body portion 175 may include an upperimpurity region (not shown). The bottom of the upper impurity region maybe higher than the top surface of the uppermost layer in the horizontalstructures HS. The upper impurity region may be doped with a differentconductive type than a portion of the semiconductor spacer 165 below theupper impurity region. The upper impurity region and a bottom regionthereof may form a diode. According to example embodiments, the upperplugs 260 may be, for example, doped silicon and/or metallic materials.

According to example embodiments, the upper plugs 260 may be, forexample, a silicon layer of a different conductive type than thesemiconductor spacer 165 and the semiconductor body portion 175. Theupper plugs 260 may form a P-N junction with the semiconductor spacer165 and the semiconductor body portion 175. Each of the upper wirings270 may be electrically connected to the semiconductor spacer 165 andthe semiconductor body portion 175 through the upper plug 260, and maycross over the horizontal structures HS. According to exampleembodiments of a NAND flash memory, the upper wirings 270 may be used asbit lines contacting one end of a plurality of cell strings.

FIGS. 12-21 are perspective views illustrating methods of fabricatingthree-dimensional semiconductor devices according to example embodimentsof the inventive concepts. For conciseness, elements which may besubstantially identical to those of example embodiments described withreference to FIGS. 1-11 may be omitted in the following description.Referring to FIGS. 1 and 12 , openings 106 penetrating the moldstructure 100 may be formed. According to example embodiments, a portionof the openings 106 may be, for example, a hexahedral shape where aspectratios of sections projected on the xy plane and the xz plane aregreater than about 5. The lengths in the y and z directions of theopening 106 may be five times of that in the x direction thereof.

Referring to FIG. 13 , a preliminary vertical pattern 154 and apreliminary semiconductor spacer 164 covering the inner wall of each ofthe openings 106 may be formed (e.g., sequentially formed). A verticallayer (not shown) and a first semiconductor layer (not shown) may beformed to cover the inner walls of the openings 106. The firstsemiconductor layer may be, for example, anisotropically etched toexpose a top surface of the substrate 10 at the bottom of the openings106. The top surface of the substrate 10 exposed by the preliminarysemiconductor spacer 164 may be recessed by over-etching during theanisotropic etch of the first semiconductor layer. The vertical layermay include one thin layer and/or a plurality of thin layers. Exampleembodiments of the inventive concepts may be diversely classifiedaccording to the thin layers of the vertical layer 150.

Referring to FIGS. 14 and 15 , a second semiconductor layer 170 andstring definition masks 182 may be formed on the structure including thepreliminary vertical pattern 154 (e.g., sequentially formed). The secondsemiconductor layer 170 may be, for example, a silicon (e.g.,polycrystalline silicon) layer formed using, for example, ALD and/orCVD. The string definition masks 182 may include an insulation materialformed using spin-on-glass (SOG) and/or a silicon oxide layer. Theforming of the string definition masks 182 may include forming a stringseparation layer (not shown) on the structure including the secondsemiconductor layer 170 to fill the openings 106 and patterning thestring separation layer to cross over the openings 106. The patterningof the string separation layer may include, for example, anisotropicallyetching the string separation layer using an etchant with etchselectivity to the second semiconductor layer 170. According to exampleembodiments, the patterning of the string separation layer may beperformed to the bottom of the opening 106 to expose the secondsemiconductor layer 170.

Each of the string definition masks 182 may include an upper pattern 182a crossing over the top of the openings 106 and extension patterns 182 bextending downwardly from the upper pattern 182 a to partially fill theopenings 106. Surfaces of the second semiconductor layer 170 between theextension patterns 182 b in the y direction may be exposed. Theextension patterns 182 b may be formed to expose the sidewalls and thebottom surface of the second semiconductor layer 170 between theextension patterns 182 b. Referring to FIG. 16 , by using the stringdefinition masks 182 as an etch mask, the second semiconductor layer 170and the preliminary semiconductor spacer 164 may be patterned (e.g.,sequentially patterned). The patterning may include, for example,isotropically etching the second semiconductor layer 170 and thepreliminary semiconductor spacer 164 using an etchant with etchselectivity to the preliminary vertical pattern 154.

According to example embodiments, the preliminary vertical pattern 154may be etched during the patterning and sidewalls of the mold structure100 may be exposed. The preliminary vertical pattern 154 may beseparated horizontally to form two-dimensionally arranged verticalpatterns 155. The preliminary semiconductor spacer 164 may be separatedhorizontally to form two-dimensionally arranged semiconductor spacers165. Between the string definition masks 182 and the mold structure 100,the two-dimensionally arranged vertical patterns 155 and semiconductorspacers 165 may be formed on the substrate 10. The second semiconductorlayer 170 may form second semiconductor patterns 174 separatedhorizontally. The second semiconductor patterns 174 may includesemiconductor body portions 175 between the semiconductor spacers 165and the string definition masks 182.

According to example embodiments, the preliminary vertical pattern 154may remain on the inner walls of the openings 106. The patterningprocess may be performed so that the sidewall of the mold structure 100is not exposed. FIG. 27 is a perspective diagram illustrating a portionof a structure according example embodiments. If the vertical layerincludes a plurality of thin layers, some thin layers of the verticallayer and/or the preliminary vertical pattern 154 may remain on theinner walls of the openings 106.

Referring to FIGS. 17 and 18 , string separation layers ISO may beformed to fill the openings 106 between the masks 182. Trenches 200penetrating the mold structure 100 may be formed to expose the sidewallsof the sacrificial layers 130 and the insulating layers 120. The stringseparation layers ISO may be formed of one or more insulation materials.The string separation layers ISO may be formed with a similar shape tothe string definition masks 182. Each of the string separation layersISO may include an upper separation pattern horizontally crossing overthe openings 106 and extension parts (not shown) extending downwardlyfrom the upper separation pattern to fill the openings 106.

The trenches 200 may be formed, for example, to cross over between theopenings 105 as described with reference to FIG. 9 . By the trenches200, the semiconductor body portions 175 of the second semiconductorpattern 174 may be separated from each other and the extension patterns182 b of the string definition mask 182 may be separated from eachother. The semiconductor body portions 175 may be two-dimensionallyarranged on the substrate 10, similarly to the vertical patterns 155 andthe semiconductor spacers 165. A plurality of vertical structures VS anda plurality of string separation layers ISO therebetween may be in oneopening 106. Each of the vertical structures VS may include onesemiconductor body portion 175, a pair of the vertical patterns 155, anda pair of the semiconductor spacers 165. The vertical structure VS mayfurther include the extension pattern 182 b.

Referring to FIG. 19 , recess regions 210 may be formed between theinsulating layers 120 by selectively removing the exposed sacrificiallayers 130. Referring to FIG. 20 , horizontal structures HS may beformed to fill the recess regions 210. The recess regions 210 and thehorizontal structures HS may be formed, for example, as described withreference to FIGS. 8 and 9 . The horizontal structure HS may includehorizontal pattern 220 covering the inner walls of the recess region 210and/or a conductive pattern 230 filling the remaining space of therecess region 210. Impurity regions 240 may be formed in the substrate10 exposed through the trench 200.

Referring to FIG. 21 , electrode separation patterns 250, upper plugs260, and upper wirings 270 may be formed. The electrode separationpatterns 250 may be formed to fill the trenches 200. Each of the upperplugs 260 may be connected to each of the vertical structures VS, andthe upper wirings 270 may be formed to connect to the upper plugs 260.The electrode separation patterns 250, the upper plugs 260 and the upperwirings 270 may be formed, for example, as described with reference toFIGS. 10 and 11 .

Three-dimensional semiconductor devices according to example embodimentsof the inventive concepts will be described with reference to FIGS.22-27 . In order to reduce complexity in the drawings and to providebetter understanding of example embodiments of the inventive concepts,some elements of three-dimensional semiconductor devices may be omitted.Those of ordinary skill in the art with knowledge of example embodimentswill understand which elements may be omitted from both the accompanyingdrawings and descriptions of fabricating methods. Additionally, forconcise description, description of overlapping elements previouslydescribed may be omitted. Because three-dimensional semiconductordevices described herein may be fabricated through modifications of theabove-mentioned fabricating methods and other different fabricatingmethods, all the described elements of disclosed fabricating method maynot necessarily be explicitly included in description ofthree-dimensional semiconductor devices.

FIGS. 22-24 are perspective views illustrating three-dimensionalsemiconductor devices fabricated according to example embodiments of theinventive concepts described with respect to FIGS. 1-11 . Referring toFIG. 22 , horizontal structures HS may be three-dimensionally arrangedon a substrate 10 (e.g., more than one element may be arranged in the zdirection) and vertical structures VS vertically penetrating thehorizontal structures HS may be two-dimensionally arranged on thesubstrate 10 (e.g., single elements may be arranged in the z direction).Each of the horizontal structures HS may include a conductive pattern230 and a horizontal pattern 220. The conductive pattern 230 may bearranged with a major axis parallel to the top surface (e.g., the xyplane) of the substrate 10. A plurality of openings 105 penetrated bythe vertical structures VS may be in the conductive pattern 230. Thehorizontal pattern 220 may be between the conductive pattern 230 and thevertical structures VS. The horizontal pattern 220 may cover the innersidewalls of the conductive pattern 230 and/or the sidewalls of theopenings 105. According to example embodiments, the horizontal patterns220 may extend horizontally from the openings 105 to cover the topsurface and the bottom surface of the conductive pattern 230.

The conductive pattern 230 may include, for example, at least one ofdoped silicon, metal materials, metal nitride layers, and/or metalsilicide. For example, the conductive pattern 230 may include a tantalumnitride layer and/or tungsten. The horizontal pattern 220 may be onethin layer and/or a plurality of thin layers. According to exampleembodiments, the horizontal pattern 220 may include, for example, ablocking insulating layer used as a memory element of a charge trap typenonvolatile memory transistor.

Each of the vertical structures VS may include a semiconductor patternSP connected to the top surface of the substrate 10 and a verticalpattern 155 between the semiconductor pattern SP and the horizontalstructures HS. According to example embodiments, the semiconductorpattern SP may include a semiconductor spacer 165 and a semiconductorbody portion 175. The semiconductor spacer 165 may be a cylindricalshape with open top and bottom entrances. The semiconductor body portion175 may be a cup shape covering the inner wall of the semiconductorspacer 165 and the top surface of the substrate. Because thesemiconductor body portion 175 may be a thickness that does notcompletely fill the opening part 105, a hole 105 a may be in thesemiconductor body portion 175. According to example embodiments, theholes 105 a may be filled by buried patterns 185.

The vertical pattern 155 may be a cylindrical shape with open top andbottom entrances and may include a bottom portion extending below thesemiconductor spacer 165. The vertical pattern 155 may be extendedvertically from between the semiconductor pattern SP and the horizontalstructures HS to cover an entire outer wall of one semiconductor patternSP. The vertical pattern 155 may be a single body around onesemiconductor pattern SP.

According to example embodiments, the semiconductor pattern SP may be amaterial with a semiconducting property. For example, each of thesemiconductor spacer 165 and the semiconductor body portion 175 may bepolycrystalline silicon, an organic semiconductor layer and/orcarbon-nano structures. The vertical pattern 155 may include one thinlayer and/or a plurality of thin layers. According to exampleembodiments, the vertical pattern 155 may include, for example, a tunnelinsulating layer used as a memory element of a charge trap typenonvolatile memory transistor.

The horizontal structures HS and the vertical structures VS may definelocalized intersecting regions therebetween, vertical adjacent regionsvertically adjacent to the intersection regions, and horizontal adjacentregions horizontally adjacent to the intersecting regions. Thevertically adjacent regions may be sidewalls of the vertical structureVS between the horizontal structures HS, and the horizontal adjacentregions may be surfaces of the horizontal structures HS disposed betweenthe vertical structures VS. According to example embodiments of theinventive concepts, the horizontal pattern 220 and the vertical pattern155 may be on the intersecting regions, and the horizontal pattern 220may extend to the horizontal adjacent regions and the vertical pattern155 may extend to the vertical adjacent regions.

Referring to FIG. 23 , the semiconductor body portion 175 maysubstantially and completely fill the opening 105 including thesemiconductor spacer 165. According to example embodiments, a void maybe formed in the semiconductor body portion 175 and the semiconductorbody portion may not fill the opening 105. The semiconductor bodyportion 175 and/or the semiconductor spacer 165 may have a differentcrystal structure than polycrystalline silicon formed through CVD, afterundergoing a crystalline structure changing step (e.g., an epitaxialtechnique including a laser annealing step). For example, thesemiconductor body portion 175 and/or the semiconductor spacer 165 mayinclude a bottom region and a top region of different grain sizes. Thesemiconductor body portion 175 and/or the semiconductor spacers 165according to example embodiments may be the same or different crystalstructure.

Referring to FIG. 24 , the length of the vertical pattern 155 may beless than that of the semiconductor spacer 165. Below the semiconductorspacer 165, there may be an under-cut region 77 on the bottom surface ofthe vertical pattern 155. This structure may be obtained byisotropically etching the bottom region of the vertical pattern 155using the semiconductor spacer 165 as an etch mask. The under-cut regionmay be filled by the semiconductor body portion 175.

FIGS. 25-27 are perspective views illustrating three-dimensionalsemiconductor devices fabricated according to example embodiments of theinventive concepts described with respect to FIGS. 12-21 . For concisedescription, overlapping description of elements previously describedwith reference to FIGS. 12-21 may be omitted. Referring to FIG. 25 ,horizontal structures HS may be three-dimensionally arranged on asubstrate 10 and vertical structures VS may be between horizontalstructures HS. The vertical structures VS may be two-dimensionallyarranged with respect to the substrate 10 and disposed to face thesidewalls of the horizontal structures HS.

Each of the horizontal structures HS may include a conductive pattern230 and a horizontal pattern 220. A major axis of the conductive pattern230 may have a line shape parallel to the top surface. The horizontalpattern 220 may be between the conductive pattern 230 and the verticalstructures VS and may horizontally extend to cover the top surface andthe bottom surface of the conductive pattern 230. One sidewall of theconductive pattern 230 spaced from the vertical structure VS may not becovered by the horizontal pattern 220. The section of the horizontalpattern 220 projected on the xz plane may have a “⊏” or “U” shape.

Each of the vertical structures VS may include a semiconductor patternSP connected to the top surface of the substrate 10 and a verticalpattern 155 between the semiconductor pattern SP and the horizontalstructures HS. According to example embodiments, one semiconductorpattern SP of one vertical structure VS may include a pair ofsemiconductor spacers 165 and one semiconductor body portion 175therebetween.

The semiconductor body portion 175 may include a pair of sidewallscrossing over the horizontal structures HS vertically and a bottomportion connecting the bottom surfaces of the sidewalls. Thesemiconductor body portion 175 may include a horseshoe-shaped portion.Each of the semiconductor spacers 165 may include, for example, ahexahedral-shaped portion between the sidewall of the semiconductor bodyportion 175 and the vertical pattern 155. The x-direction thicknesses ofthe sidewall of the semiconductor body portion 175 and the semiconductorspacer 165 may be less than an interval between a pair of thehorizontally-adjacent conductive patterns 230. As illustrated in FIG. 15, the extension pattern 182 b of the string definition mask 182 may bedisposed between the sidewalls of the semiconductor body portion 175.

The vertical pattern 155 may be, for example, a hexahedral shape but anx-direction thickness may be less than an interval between a pair of thehorizontally-adjacent conductive patterns 230. The vertical pattern 155may be, for example, an elongated plate shape. The vertical pattern 155may be horizontally extended with a bottom portion under thesemiconductor spacer 165, and may be horizontally and continuouslyextended to entirely cover one sidewall of the semiconductor spacer 165.Referring to FIGS. 26 and 27 , the semiconductor body portion 175 maysubstantially and completely fill the opening 106 including thesemiconductor spacer 165. According to example embodiments, adiscontinuous interface 179 and/or void may be formed in thesemiconductor body portion 175. As described with reference to FIG. 23 ,the semiconductor body portion 175 and/or the semiconductor spacer 165may have a different crystal structure than polycrystalline siliconformed through CVD, after undergoing a crystalline structure changingstep (e.g., an epitaxial technique including a laser annealing step).

Referring to FIG. 27 , the vertical pattern 155 may include a horizontalextension part 155 e extending horizontally, as described with referenceto FIG. 16 . The horizontal extension part 155 e may be between thehorizontally-adjacent semiconductor body portions 175 to contact thesidewall of the string separation layer ISO. According to exampleembodiments related to a charge trap type nonvolatile memory device, thevertical pattern 155 may include a tunnel insulating layer TIL and acharge storing layer CL, and/or a capping layer CPL. According toexample embodiments, the horizontal extension part 155 e may includeboth the tunnel insulating layer TIL and the charge storing layer CL.According to example embodiments, the horizontal extension part 155 emay include only the capping layer CPL, and the charge storing layer CLand the tunnel insulating layer TIL may be horizontally separated by thestring separation layer ISO. This separation may be realized, forexample, by using the fabricating methods described with reference toFIG. 16 .

FIGS. 28-43 are perspective views illustrating structures of informationstoring layers according to example embodiments of the inventiveconcepts. According to example embodiments of a charge trap typenonvolatile memory device, the horizontal pattern 220 and the verticalpattern 155 may be part of an information storing layer of a memory celltransistor. The number and types of thin layers constituting each of thehorizontal and vertical patterns 220 and 155 may vary, and based on thisdiversity, example embodiments of the inventive concepts may beclassified into several example embodiments. For example, exampleembodiments of the inventive concepts related to the information storinglayer may be classified as in the following Table 1.

TABLE 1 Information storage layer Corresponding VS HS figure SP TIL CLCPL BIL1 230 28/36^([1]) SP TIL CL BIL1 230 29/37 SP TIL CL BIL1 23030/38 SP TIL CL BIL1 BIL2 230 31/39 SP TIL CL BIL1 BIL2 230 32/40 SP TILCL CPL BIL1 230 33/41^([2]) SP TIL CL CPL BIL1 230 34/42^([3]) SP TIL CLCPL BIL1 BIL2 230 35/43 TIL: Tunnel Insulating layer BIL: BlockingInsulating Layer CL: Charge storing Layer CPL: Capping Layer ^([1])CPLwith uniform thickness ^([2])CPL with recessed sidewall ^([3])CPLseparated vertically

According to example embodiments of a flash memory, the informationstoring layer may include a tunnel insulating layer TIL, a chargestoring layer CL, and a first blocking insulating layer BIL1 (e.g., asshown in Table 1 and illustrated in FIGS. 28-43 ). According to exampleembodiments, the information storing layer may include a second blockinginsulating layer BIL2 between the first blocking insulating layer BIL1and the conductive pattern 230. The information storing layer mayinclude a capping layer CPL interposed between the charge storing layerCL and the first blocking insulating layer BIL1. Layers of theinformation storing layer may be formed using a deposition techniqueproviding, for example, excellent and/or improved stepped application(e.g., a CVD and/or ALD technique).

The vertical structure VS may include the tunnel insulating layer TILand the horizontal structure HS may include at least one of the firstand second blocking insulating layers BIL1 and BIL2. According toexample embodiments (e.g., as illustrated in FIGS. 28, 29, 31, 33-37, 39and 41-43 ), the vertical structure VS may include the charge storinglayer CL. According to example embodiments (e.g., as illustrated inFIGS. 30, 32, 38 and 40 ), the horizontal structure HS may include thecharge storing layer CL. If the vertical structure VS includes thecharge storing layer CL (e.g., as illustrated in FIGS. 28, 33-36 and41-43 ) the vertical structure VS may include the capping layer CPL. Thevertical structure VS and the horizontal structure HS may directlycontact and may not include the capping layer CPL (e.g., as illustratedin FIGS. 29, 31, 37 and 39 ).

The sidewall thickness of the capping layer CPL may be non-uniform. Forexample, during the forming of the recess regions 210, the sidewall ofthe capping layer CPL adjacent to the horizontal structure HS may behorizontally recessed. The thickness of the capping layer CPL may bethicker in a region “b” (or a vertical adjacent region) between thehorizontal structures HS than in a region “a” (or a channel region)adjacent to the horizontal structure HS (e.g., as illustrated in FIGS.33 and 41 ). The capping layer CPL may locally remain on the verticaladjacent region “b”, and the horizontal structure HS may directlycontact the sidewall of the charge storing layer CL in the channelregion “a” (e.g., as illustrated in FIGS. 34 and 42 ). The sidewallthickness of the capping layer CPL may be substantially uniform (e.g.,as illustrated in FIGS. 28 and 36 ).

According to example embodiments the horizontal structure HS may includeboth of the first and second blocking insulating layers BIL1 and BIL2(e.g., as illustrated in FIGS. 31, 32, 35, 39, 40 and 43 ). The chargestoring layer CL may be one or more insulating layers with abundant trapsites and/or one or more insulating layers with nano particles and maybe formed, for example, by CVD and/or ALD. For example, the chargestoring layer CL may include one of a trap insulating layer and/or aninsulating layer with a floating gate electrode and/or conductive nanodots. The charge storing layer CL may include a silicon nitride layer, asilicon oxynitride layer, a silicon-rich nitride layer, a nanocrystalline silicon layer, and/or a laminated trap layer.

The tunnel insulating layer TIL may be one of materials with a higherband gap than the charge storing layer CL, and may be formed by, forexample, CVD and/or ALD. For example, the tunnel insulating layer TILmay be a silicon oxide layer. The tunnel insulating layer TIL mayundergo a thermal treatment performed after a deposition process. Thethermal treatment process may be, for example, a rapid thermalnitridation (RTN) process and/or an annealing process in an atmosphereincluding nitrogen and/or oxygen.

The first and second blocking insulating layers BIL1 and BIL2 may bedifferent materials, and one of them may be one of materials having asmaller band bap than the tunnel insulating layer TIL and a larger bandgap than the charge storing layer CL. The first and second blockinginsulating layers BIL1 and BIL2 may be formed by, for example, CVDand/or ALD. At least one of BIL1 and BIL2 may be formed by wetoxidation. According to example embodiments, the first blockinginsulating layer BIL1 may be one of high-k dielectric layers (e.g., analuminum oxide layer and/or a hafnium oxide layer). The second blockinginsulating layer BIL2 may be, for example, a material with a smallerdielectric constant than the first blocking insulating layer BIL1.According to example embodiments, the second blocking insulating layerBIL2 may be a high-k dielectric layer and the first blocking insulatinglayer BIL1 may be of a material with a smaller dielectric constant thanthe second blocking insulating layer BIL2. According to exampleembodiments, a third blocking insulating layer (not shown) may beincluded between the charge storing layer CL and the conductive pattern230.

The capping layer CPL may be a material providing etch selectivity withrespect to the charge storing layer CL and/or the sacrificial layer 130.For example, if the sacrificial layer 130 is a silicon nitride layer,the capping layer CPL may be a silicon oxide layer. During a process forremoving the sacrificial layer 130 to form the recess regions 210, thecapping layer CPL may be an etch stop layer to prevent and/or reduceetch damage of the charge storing layer CL. If the capping layer CPL mayremain between the conductive pattern 230 and the charge storing layerCL (e.g., as shown in FIGS. 28, 33, 35, 36, 41 and 43 ), the cappinglayer CPL may be a material contributing to preventing leakage (e.g.,back-tunneling) of charge stored in the charge storing layer CL. Forexample, the capping layer CPL may be one of a silicon oxide layer and ahigh-k dielectric layer.

FIGS. 44-46 are cross-sectional diagrams illustrating three-dimensionalsemiconductor devices according to example embodiments. Referring toFIGS. 44-46 , at least one upper selection line USL may be between theupper wiring 270 and the horizontal structures HS. The upper selectionline USL may be a gate electrode of an upper selection transistorcontrolling a flow of current passing through the upper wiring 270 andthe semiconductor pattern SP. The upper selection transistor may be ametal-oxide-semiconductor field-effect transistor (MOSFET) and mayinclude an upper gate insulating layer UGI between the upper selectionline USL and the semiconductor pattern SP. In order to control thecurrent flow, the upper selection line USL may be arranged in adirection intersecting the upper wiring 270 (e.g., a direction parallelto the horizontal structure HS and/or the conductive pattern 230).

According to example embodiments, the upper selection line USL may beformed through a different process than the conductive pattern 230 ofthe horizontal structure HS. According to example embodiments, the upperselection line USL and the conductive pattern 230 may be formed throughthe same process and may be substantially formed of the same material.According to example embodiments, the upper gate insulating layer UGImay be formed through the same process as one of the horizontal pattern220 and the vertical pattern 155, such that it may be substantially thesame material and thickness as one of the horizontal pattern 220 and thevertical pattern 155. The upper gate insulating layer UGI may include athin layer of one of the horizontal pattern 220 and/or the verticalpattern 155. According to example embodiments, the upper gate insulatinglayer UGI may be separately formed through a different fabricatingprocess than the horizontal pattern 220 and the vertical pattern 155.

Referring to FIGS. 45 and 46 , an upper semiconductor pattern USP may bebetween the upper wiring 270 and the semiconductor pattern SP, and theupper selection line USL may be around the upper semiconductor patternUSP. According to example embodiments, the upper semiconductor patternUSP may be of the same conductive type as the semiconductor pattern SP.A pad may be between the upper semiconductor pattern USP and the upperplug 260. Referring to FIG. 46 , a lower selection line LSL of at leastone layer may be between the substrate 10 and the horizontal structuresHS. A lower semiconductor pattern LSP may be between the substrate 10and the semiconductor pattern SP, and the lower selection line LSL maybe around the lower semiconductor pattern LSP. The lower selection lineLSL may be a gate electrode of a lower selection transistor controllinga flow of current passing through the impurity region 240 and thesemiconductor pattern SP. A lower gate insulating layer LGI (or a lowergate insulating layer) may be interposed between the lower selectionline LSL and the lower semiconductor pattern LSP.

FIGS. 47 and 48 are perspective views illustrating three-dimensionalsemiconductor devices according to example embodiments. Referring toFIGS. 47 and 48 , a vertical conductive plate 255 contacting theimpurity region 240 may be in the trench 200. For electrical separationbetween the vertical conductive plate 255 and the conductive patterns230, trench spacers 245 may be on the sidewall of the trench 200. Thevertical conductive plate 255 may be a conductive material (e.g., atleast one of metallic materials such as tungsten). A barrier metal layer(e.g., a metal nitride (not shown)) and/or a silicide layer (not shown))may be between the impurity region 240 and the vertical conductive plate255. The trench spacers 245 may be formed of an insulation material(e.g., a silicon oxide layer).

The vertical conductive plate 255 and the trench spacer 245 may beformed after the forming of the impurity region 240 described withreference to FIGS. 9 and 20 . By forming an insulating layer thatconformally covers the inner wall of the trench 200 and thenanisotropically etching the resultant structure to expose the topsurfaces of the impurity regions 240, the trench spacer 245 may beformed. By filling the trench (having the trench spacer 245) with abottom conductive layer and then performing a planarization etch step,the vertical conductive plate 255 may be formed. The vertical conductiveplate 255 and the trench spacer 245 may vertically penetrate theconductive patterns 230 and horizontally cross over the semiconductorpatterns SP. According to example embodiments, the thickness (e.g., a“z” direction length) of the vertical conductive plate 255 may besubstantially identical to that of the trench 200.

Because the vertical conductive plate 255 may be a lower resistivitythan the impurity region 240 and may be connected to the impurity region240, it may contribute to improving a transmission speed of anelectrical signal passing through the impurity regions 240. Because atop surface of the vertical conductive plate 255 may be higher than thatof the uppermost layer among the conductive patterns 230, technicaldifficulties of a wiring formation process for electrical connection tothe impurity region 240 may be reduced. Because the vertical conductiveplate 255 may be a shielding layer between the conductive patterns 230,a capacitive coupling between horizontally adjacent conductive patterns230 may be reduced. Disturbance may be reduced during program and readoperations.

A punch-and-plug technique may be used for three dimensionally realizinga flash memory device equipped with a charge storing layer as a memoryelement. According to an order of forming an information storing layerand a semiconductor plug used as an active region, the punch-and-plugtechnique may be classified into a storage-first method. An informationstoring layer may be formed before the semiconductor plug. For example,according to the storage-first method, the tunnel insulating layer TIL,the charge storing layer CL and the blocking insulating layer BIL, usedas a memory element and/or the information storing layer, may be formedto cover the inner wall of, for example, the opening 105. According to aplug-first method, a semiconductor plug may be formed before theinformation storing layer. According to the plug-first method, thetunnel insulating layer TIL, the charge storing layer CL and theblocking insulating layer BIL, used as a memory element and/or theinformation storing layer, may be formed, for example, to cover surfacesof the conductive pattern 230.

According to the storage-first method, the opening 105 may be formedafter depositing the word line WL. Owing to technical difficulties inthe forming of the opening 105, the word line WL according to thestorage-first method may be formed of, for example, dopedpolycrystalline silicon with a relatively higher resistivity than metal.According to example embodiments of the inventive concepts, for exampleas described with reference to FIGS. 9 and 20 , the word line WL (e.g.,the conductive pattern 230) may be formed after the forming of theopening 105/106. Accordingly, in example embodiments of the inventiveconcepts, the conductive pattern 230 may be metallic.

In the plug-first method, after forming recess regions 210 betweeninsulating layers 120, layers constituting the memory element and theconductive pattern 230 may be sequentially deposited on the inner wallsof the recess regions 210. All layers constituting the memory element(i.e., the tunnel insulating layer TIL, the charge storing layer (CL)and the blocking insulating layer (BIL)) may fill the recess regions210, and a thickness of the conductive pattern 230 should be reducedcompared to the recess region 210. This reduction of thickness may causetechnical difficulties, for example, an increase of a vertical distancebetween the conductive patterns 230 and a resistance increase of theconductive pattern 230. These difficulties may become worse asintegration density is increased. According to example embodiments ofthe inventive concepts, because some layers constituting a memoryelement (i.e., the horizontal pattern 220) may fill the recess regions210, the technical difficulties in the plug-first method may besuppressed.

In relation to the information storing layer, the various exampleembodiments of the inventive concepts may be described with reference toTable 1 and FIGS. 28-43 . According example embodiments, each of thethin layers included in the information storing layer may be part of thevertical structure VS or the horizontal structure HS. According toexample embodiments (e.g., with reference to FIGS. 49-54 ), at least onelayer in the vertical structure VS and at least one layer in thehorizontal structure HS may provide a same function. In the followingdescription, these layers of the same function may be referred to as acrossing structure CS. Although at least two layers of the informationstoring layer (e.g., the crossing structure CS) may be independentlyformed by the storage-first method or the plug-first method, they maycommonly have physical properties required for one of a charge storingelement, a tunneling element, and a blocking element.

FIGS. 49 and 50 are cross-sectional diagrams illustrating exampleembodiments of a charge storing element as a crossing structure CS.FIGS. 51 and 52 are cross-sectional diagrams illustrating exampleembodiments of a blocking element realized as a crossing structure CS.FIGS. 53 and 54 are cross-sectional diagrams illustrating exampleembodiments of a tunneling element realized as a crossing structure CS.

Referring to FIGS. 49 and 50 , the vertical structure VS and thehorizontal structure HS may include a first charge storing layer CL1 anda second charge storing layer CL2, respectively. The first and secondcharge storing layers CL1 and CL2 may include a material with physicalproperties for storing charges. The first and second charge storinglayers CL1 and CL2 may be formed through the storage-first method andthe plug-first method, respectively, and may be of a material with asmaller band gap than the blocking insulating layer BIL and a highertrap density than a silicon oxide.

According to example embodiments, the first and second charge storinglayers CL1 and CL2 may be of substantially the same material in at leastone of a chemical composition and/or an electrical property, and mayprovide a same function required from the crossing structure CS. Thefirst and second charge storing layers CL1 and CL2 do not need to be thesame with respect to chemical composition and/or electrical property.For example, although two kinds of atoms with the highest content of thefirst charge storing layer CL1 may be identical to those of the secondcharge storing layer CL2, the content ratios of the two kinds of atomsare not necessarily identical in the first and second charge storinglayers CL1 and CL2. For example, the first and second charge storinglayers CL1 and CL2 may be a silicon nitride layer including silicon andnitride atoms, but a content ratio of silicon and nitride atoms may bedifferent between the first and second charge storing layers CL1 andCL2.

Referring to FIGS. 51 and 52 , the vertical structure VS and thehorizontal structure HS may include a first blocking insulating layerBIL1 and a second blocking insulating layer BIL2, respectively, and thefirst and second blocking insulating layers BIL1 and BIL2 may include amaterial with a blocking property. The first and second blockinginsulating layers BIL1 and BIL2 may be formed through the storage-firstmethod and the plug-first method, respectively. One of the first andsecond blocking insulating layers BIL1 and BIL2 may include a materialwith a smaller band gap than the tunnel insulating layer TIL and alarger band gap than the charge storing layer CL.

According example embodiments, in relation to the first and secondblocking insulating layers BIL1 and BIL2, in order to provide a samefunction of a crossing structure CS, at least one of a chemicalcomposition or an electrical property may be substantially the same.However, the first and second blocking insulating layers BIL1 and BIL2do not need to be the same with respect to chemical composition and/orelectrical property. For example, the first blocking insulating layerBIL1 may be a high-k dielectric layer (e.g., an aluminum oxide layerand/or a hafnium oxide layer) and the second blocking insulating layerBIL2 may be include a material with a smaller dielectric constant thanthe first blocking insulating layer BIL1. According to exampleembodiments, the second blocking insulating layer BIL2 may be a high-kdielectric layer and the first blocking insulating layer BIL1 mayinclude a material with a smaller dielectric constant than the secondblocking insulating layer BIL2.

Referring to FIGS. 53 and 54 , the vertical structure VS and thehorizontal structure HS may include a first tunnel insulating layer TIL1and a second tunnel insulating layer TIL2, respectively, and the firstand second tunnel insulating layers TIL1 and TIL2 may include a materialwith a charge tunneling property. The first and second tunnel insulatinglayers TIL1 and TIL2 may be formed through the storage-first method andthe plug-first method, respectively, and one of the first and secondtunnel insulating layers TIL1 and TIL2 may be a material with a largerband gap than the charge storing layer CL.

According to example embodiments, in relation to the first and secondtunnel insulating layers TIL1 and TIL2, in order to provide a samefunction of a crossing structure CS, at least one of a chemicalcomposition and/or an electrical property may be substantially the same.However, the first and second tunnel insulating layers TIL1 and TIL2 donot need to be the same with respect to chemical composition and/orelectrical property. According to example embodiments, the first andsecond tunnel insulating layers TIL1 and TIL2 may include thin layers ofrespectively different chemical compositions.

According to example embodiments of the inventive concepts a portion ofthe crossing structure CS constituting the vertical structure VS mayremain between the conductive pattern 230 and the sidewalls of thesemiconductor pattern SP (e.g., as illustrated in FIGS. 49, 51, and 53). A thickness 51 of the crossing structure CS measured between theconductive pattern 230 and the sidewalls of the semiconductor pattern SPmay be greater than S2 of the crossing structure CS measured between thetop and the bottom of the conductive pattern 230. A three-dimensionalshape of the crossing structure CS with S1>S2 is illustrated in FIGS. 55and 56 . FIG. 55 is a perspective view illustrating a crossing structureCS according to the fabricating methods described with reference toFIGS. 1-11 . FIG. 56 is a perspective view illustrating a crossingstructure CS according to the fabricating methods described withreference to FIGS. 12-21 .

According to example embodiments of the inventive concepts, a portion ofthe crossing structure CS of the vertical structure VS may be removedbetween the conductive pattern 230 and the sidewalls of thesemiconductor pattern SP (e.g., as illustrated in FIGS. 50, 52, and 54). The portion of the crossing structure CS of the vertical structure VSmay locally remain between the conductive patterns 230 in a verticalposition. A thickness 51 of the crossing structure CS measured betweenthe conductive pattern 230 and the sidewalls of the semiconductorpattern SP may be substantially identical to that S2 of the crossingstructure measured between the top and the bottom of the conductivepatterns 230. A thickness S3 of the crossing structure CS of thevertical structure VS may be different from that S2 of the crossingstructure CS of the horizontal structure HS. According to exampleembodiments, the thickness S2 may be greater than the thickness S3, thethickness S2 may be less than the thickness S3 or the thickness S2 maybe substantially the same as the thickness S3.

FIGS. 57-66 are cross-sectional diagrams illustrating methods offabricating the three-dimensional semiconductor devices described withreference to FIG. 46 and other example embodiments. Referring to FIG. 57, after forming of a bottom mold structure 101 on a substrate 10, aselection active pattern SAP penetrating the bottom mold structure 101may be formed. An upper mold structure 102 may be formed on thestructure with the selection active pattern SAP. Each of the lower andupper mold structures 101 and 102 may be formed by, for example, usingmethods of fabricating the mold structure 100 described with referenceto FIG. 1 . The lower and upper mold structures 101 and 102 may be amold structure 100.

Each of the lower mold structure 101 and the upper mold structure 102may include insulating layers 120 alternating with sacrificial layers130 (e.g., repeatedly stacked). The forming of the selection activepattern SAP may include, after forming of holes and/or openingspenetrating the lower mold structure 101, filling the holes and/oropenings with a material with a semiconducting property (e.g., asemiconductor layer). The holes and openings may be shaped and arrangedsimilarly to example embodiments described with reference to FIGS. 2 and12 . The semiconductor layer may be formed by, for example, CVD. Aprocess for planarizing the semiconductor layer may be performed toexpose a top surface of the lower mold structure 101. The selectionactive pattern SAP may be a structure obtained by performing theplanarization process on the semiconductor layer.

The selection active pattern SAP may be formed of, for example, asemiconductor of a same conductive type as the substrate 10 or anintrinsic semiconductor. For example, in case of a semiconductormaterial (e.g., a silicon wafer) having the same conductive type as thesubstrate 10, the selection active pattern SAP may be a p-type orintrinsic semiconductor. According to example embodiments, the selectionactive pattern SAP may be formed of a semiconductor material of apolycrystalline structure (e.g., polycrystalline silicon). According toexample embodiments, the semiconductor layer may be formed using anepitaxial technique and/or a laser crystallization technique. Theselection active pattern SAP may be a single crystal structure and/or apolycrystalline structure with a larger grain size than obtained by aCVD technique. A material of the selection active pattern SAP may besilicon but example embodiments of the inventive concepts are notlimited thereto. For example, carbon nano structures, organicsemiconductor materials and/or compound semiconductors may be used forthe selection active pattern SAP.

Referring to FIGS. 58-61 , a vertical structure VS penetrating the uppermold structure 102 may be formed to contact the selection active patternSAP. Trenches 200 penetrating the mold structure 100 may be formed.Referring to FIG. 60 , by selectively removing the sacrificial layers130 with sidewalls exposed by the trenches 200, recess regions 210exposing the vertical structure VS and the sidewalls of the selectionactive pattern SAP may be formed. Referring to FIG. 61 , horizontalstructure HS filling the recess regions 210 may be formed.

The vertical structure VS and the horizontal structure HS may be formedusing methods of fabricating three-dimensional semiconductor devicesdescribed with reference to FIGS. 1-11 and/or with reference to FIGS.12-21 . The vertical structure VS may include a vertical pattern 155, asemiconductor spacer 165, a semiconductor body portion 175 and/or aburied pattern 185. The horizontal structure HS may include horizontalpatterns 220 covering the inner wall of the recess region and aconductive pattern 230 filling the remaining spaces of the recess region210. The vertical pattern 155 and the horizontal pattern 220 may be thesame or similar to that described with reference to FIGS. 1-43 .According to example embodiments, the semiconductor layer and theselection active pattern SAP may be formed to fill the holes and/or theopenings. The selection active pattern SAP may be, for example,substantially formed with a rectangular shape. If the sidewalls of theholes and/or the openings are not vertical to the top surface of thesubstrate 10, the selection active pattern SAP may be substantiallyformed with, for example, a trapezoidal shape.

According to example embodiments of the inventive concepts, a portion ofthe bottom region of the semiconductor body portion 175 may extend intothe top surface of the selection active pattern SAP (e.g., similarly toFIG. 61 ). The selection active pattern SAP positioned at the bottom ofthe semiconductor body portion 175 may be formed with, for example, arectangular and/or trapezoidal shape. This structure may be a result ofover-etch during the forming of the semiconductor body portion 175.

Referring to FIGS. 62-66 , the selection active pattern SAP may includesidewalls covering the inner sidewalls of the holes and/or the openingsand a bottom portion contacting the top surface of the substrate 10.According to example embodiments, because the sidewalls and the bottomportion of the selection active pattern SAP may be formed with aconformal thickness, the selection active pattern SAP may have aU-shaped. According to example embodiments related to methods offabricating a three-dimensional semiconductor device described withreference to FIG. 46 , referring to FIG. 63 , a selection gateinsulating layer LGI may be selectively formed on the exposed sidewallof the selection active pattern SAP. Referring to FIG. 64 , conductivepatterns 230 and impurity regions 240 filling the recess regions 210 maybe formed. A vertical pattern 155 may include a tunnel insulating layer,a charge storing layer and a blocking insulating layer. According toexample embodiments, an insulation thin film covering the inner wall ofthe recess region 210 may be formed (e.g., before the forming of theconductive patterns 230). The insulation thin layer may be used as apart of the blocking insulating layer.

According to example embodiments, the selection gate insulating layerLGI may be formed through a thermal treatment process TT1 forselectively oxidizing the exposed sidewall of the selection activepattern SAP with a gas atmosphere including oxygen atoms. The selectiongate insulating layer LGI may be a thermal oxide layer and may belocally formed on the exposed sidewall of the selection active patternSAP and the top surface of the substrate 10 exposed by the trench 200.Because a thermal oxide layer is formed through reaction of oxygen atomsand silicon atoms of the selection active pattern SAP, silicon atoms onthe surface of the selection active pattern SAP may be consumed.Referring to FIG. 67 , thickness W1 of the selection gate insulatinglayer LGI or the selection active pattern SAP on or below the conductivepattern 230 may be greater than the thickness W2 of the selection activepattern SAP around the selection gate insulating layer LGI.

The thermal treatment process TT1 may be performed in a gas atmosphereincluding oxygen atoms. During the thermal treatment, the exposedsurface of the vertical structure VS may be a vertical pattern formednot of a silicon layer but rather insulation materials. Accordingly, theselection gate insulating layer LGI may not be substantially formed onthe sidewall of the vertical structure VS (e.g., the vertical patternmay not be substantially oxidized).

According to example embodiments related to methods of fabricating athree-dimensional semiconductor device described with reference to FIG.46 , referring to FIG. 65 , conductive lines 135 used as gate lines of aselection transistor may be formed (e.g., before the forming of theupper mold structure 102). According to example embodiments, insulatinglayers 120 and conductive layers (not shown) may be sequentially andalternately stacked on the substrate 10. Holes and/or openingspenetrating the insulating layers 120 and the conductive layers may beformed. A selection gate insulating layer LGI and selection activepatterns SAP filling the holes and/or the openings may be formed (e.g.,sequentially formed). The upper mold structure 102 may be formed on thestructure including the selection active patterns SAP. According toexample embodiments, the conductive lines 135, the selection gateinsulating layer LGI and the selection active pattern SAP may be formedthrough the storage-first method described with reference to FIG. 49 .

According to example embodiments, the conductive lines 135 may be, forexample, doped polycrystalline silicon. Referring to FIG. 66 , the lowerselection line LSL may be formed to include the conductive line 135 ofpolycrystalline silicon and a metal silicide pattern 137. For example,after the forming of the recess regions 120, a metal layer filling therecess region 210 and the trench 200 completely or partially may beformed and a silicide forming process for reacting the metal layer withthe conductive line 135 of polycrystalline silicon may be performed. Aportion of the conductive line 135 may be silicided to form the metalsilicide pattern 137. (A metal layer filling the recess regions 210 ofthe upper mold structure 102 may be maintained without reaction.) Themetal layer remaining in the trench and not participating in thesilicide forming process may be removed. FIG. 66 may illustrate astructure after the metal layer is removed.

FIGS. 68 and 69 are cross-sectional diagrams to comparethree-dimensional semiconductor devices according to example embodimentsof the inventive concepts. FIGS. 68 and 69 illustrate a current path inthe three-dimensional semiconductor device described with reference toFIGS. 1-21 and a current path in the three-dimensional semiconductordevice described with reference to FIGS. 57-64 . Referring to FIG. 68 ,in a three-dimensional semiconductor device described with reference toFIGS. 1-21 , because of the presence of the vertical pattern 155inserted at the predetermined depth in the top surface of the substrate10, a current path P1 passing through the impurity region 240 mayincrease.

It may be required that an inversion region be selectively formed in thesubstrate 10 for the current path P1, but the vertical pattern 155 mayprevent generation of the inversion region. Because the inversion regionis formed by voltage applied to the lowermost conductive pattern 230,resistance of the inversion region may be exponentially increased as adistance in a straight line from the lowermost conductive pattern 230 isincreased. According to simulation, when the depth that the verticalpattern 155 is inserted into the substrate 10 is increased from 0 nm to70 nm, resistance may be increased 10¹⁰ times. Referring to FIG. 69 ,when the selection active pattern SAP is extended on the substrate 10without the vertical pattern 155, since a current path P2 is formedadjacent to the lowermost conductive pattern 230, lengthening of thecurrent path and exponential increase of electrical resistance may beprevented and/or reduced.

FIGS. 70-82 are cross-sectional diagrams illustrating exampleembodiments with respect to forming an under-cut region 77 describedwith reference to FIG. 24 . Three-dimensional semiconductor devicesincluding the under-cut region 77 on a bottom surface of the verticalpattern 155, and methods of fabricating the semiconductor devices may bedescribed. Methods of forming the under-cut region 77 and structuresaccording thereto are not limitedly applied to the structure shown inFIG. 24 . Those skilled in the art may easily apply the inventiveconcepts according to example embodiments related to the under-cutregion 77 and an expansive description may be omitted. Furthermore, eachof the following described methods may be applied instead to the methodsof fabricating described with reference to FIGS. 3-6 and/or FIGS. 13-14. Other methods may be performed based on following methods (e.g., stepsdescribed with reference to FIGS. 7-11 and/or FIGS. 15-21 ).

Although multiple example embodiments are described with respect toFIGS. 70-82 , overlapping description may be omitted for brevity.

Referring to FIG. 70-73 , a mold structure 100 including an insulatinglayer 121 and a sacrificial layer 131 may be formed on a substrate 10.An opening 105 may be formed to penetrate the mold structure 100 toexpose the top surface of the substrate 10, and a vertical layer 150 anda first semiconductor layer 160 may be formed on the inner wall of theopening 105 (e.g., sequentially formed). The mold structure 100 may besubstantially identical to that of the embodiment described withreference to FIG. 1 . For example, an insulating layer 121 and asacrificial layer 131 may illustrate a portion of the mold structure 100and the mold structure 100 may include more insulating layers andsacrificial layers as shown in FIG. 1 .

The opening 105 may be formed with, for example, a hole shape (e.g.,similarly to FIG. 2 ) and/or to include a portion of a hexahedral shape(e.g., similarly to FIG. 12 ). According to example embodiments, duringthe forming of the opening 105, the top surface of the substrate 10 maybe recessed. The bottom surface of the opening 105 may become lower thanthe uppermost surface of the substrate 10 contacting the bottom surfaceof the insulating layer 121. The recess of the substrate 10 may formedby over-etch of the opening 105. The recess of the substrate 10 maycontribute to improving structural stability of the vertical pattern155. The vertical layer 150 and the first semiconductor layer 160 may beformed to conformally and substantially cover the sidewall and bottomsurface of the opening 105. A sum of deposition thicknesses of thevertical layer 150 and the first semiconductor layer 160 may be lessthan the half of a width of the opening 105. The opening 105 may not becompletely filled by the vertical layer 150 and the first semiconductorlayer 160.

The vertical layer 150 and the first semiconductor layer 160 may beformed as the vertical structure VS according to, for example, exampleembodiments described with reference to FIGS. 28-43 . For example, thevertical layer 150 may include a capping layer CPL, a charge storinglayer CL and a tunnel insulating layer TIL, which may be sequentiallydeposited as shown in FIG. 70 . Material and property of each of thecapping layer CPL, the charge storing layer CL and the tunnel insulatinglayer TIL may be substantially identical to example embodimentsdescribed with reference to FIGS. 28-43 . The first semiconductor layer160 may be, for example, a polycrystalline silicon layer. Referring toFIG. 71 , a penetrating dent PD exposing the top surface of thesubstrate 10 at the bottom of the opening 105 may be formed by, forexample, anisotropically etching the first semiconductor layer 160 andthe vertical layer 150. The forming of the penetrating dent PD, asdescribed with reference to FIG. 4 , may be performed through a plasmadry etch method using the mold structure 100 as an etch mask.

A semiconductor spacer 165 covering the inner sidewall of the verticalpattern 155 may be formed by the etch. The penetrating dent PD may beformed to penetrate the vertical layer 150 covering the bottom surfaceof the opening 105. The vertical pattern 155 with sidewalls exposed bythe penetrating dent PD may be formed. For a thin layer structure (e.g.,as described with reference to FIG. 71 ), sidewalls of the capping layerCPL, the charge storing layer CL and the tunnel insulating layer TIL maybe exposed by the penetrating dent PD at about the bottom of the opening105. Referring to FIG. 72 , a first under-cut region UC1 may formed byisotropically etching the exposed charge storing layer CL. The firstunder-cut region UC1 may be a gap region extending from the penetratingdent PD, and may be formed to partially expose the surfaces of thecapping layer CPL and the tunnel insulating layer TIL. According toexample embodiments, the charge storing layer CL may be, for example, asilicon nitride layer. The first under-cut region UC1 may be formedthrough a wet etch process using, for example, an etchant withphosphoric acid. According to example embodiments, the first under-cutregion UC1 may be formed using an isotropic dry etch method.

Referring to FIG. 73 , the capping layer CPL and the tunnel insulatinglayer TIL, exposed by the first undercut region UC1, may beisotropically etched to form a second undercut region (not shown). Thesecond undercut region may be formed to expose not only a portion of thesurface of the substrate 10 defining the opening 105 and covered by thecapping layer CPL, but also a lower region of an outer sidewall and abottom surface of the semiconductor spacer 165 covered by the tunnelinsulating layer TIL. The second undercut region and the first undercutregion UC1 may constitute the undercut region 77. The forming of thesecond under-cut region may be performed using, for example, at leastone of a wet etch and isotropic dry etch method. A wet etch method withan etchant including hydrofluoric acid and/or sulfuric acid may be used.

A second semiconductor layer 170 connecting the substrate 10 with thesemiconductor spacer 165 may be formed in the under-cut region 77. Thesecond semiconductor layer 170 may be formed of a semiconductor material(e.g., polycrystalline silicon) formed using a deposition technique. Thesecond semiconductor layer 170 may extend from the under-cut region 77to cover the inner wall of the semiconductor spacer 165. As a result ofa deposition process, the second semiconductor layer 170 may have a seam88 in the under-cut region 77.

Referring to FIGS. 74 and 75 , according to example embodiments of theinventive concepts, the forming of the first under-but region UC1described with reference to FIG. 72 may include, for example,isotropically etching the capping layer CPL and the tunnel insulatinglayer TIL (e.g., before the charge storing layer CL). The capping layerCPL and the tunnel insulating layer TIL may be etched using wet etchand/or isotropic dry etch methods. For example, an etchant includinghydrofluoric acid and/or sulfuric acid may be used. Referring to FIG. 75, the charge storing layer CL may be etched. A bottom surface of thecharge storing layer CL may be further spaced from the bottom surface ofthe opening 105 than at least one of the capping layer CPL or the tunnelinsulating layer TIL. The charge storing layer CL may be recessed withrespect to the capping layer CPL or the tunnel insulating layer TIL. InFIG. 73 , the capping layer CPL and the tunnel insulating layer TIL maybe recessed with respect to the charge storing layer CL.

Referring to FIGS. 76-80 , according to example embodiments of theinventive concepts, a first semiconductor layer 160 may be formed.Referring to FIG. 76 , a protective layer spacer PS may be formed in anopening 105. The protective layer spacer PS may be formed of a materialwith etch selectivity to the first semiconductor layer 160. According toexample embodiments, the protective layer spacer 165 may be, forexample, a silicon oxide layer and/or a silicon nitride layer formedusing ALD. The protective layer spacer PS may be formed thinner thanhalf the difference between the half of the width of the opening 105 andthe sum of deposition thicknesses of the vertical layer 150 and thefirst semiconductor layer 160. The opening 105 may not be completelyfilled by the protective layer spacer PS.

A penetrating dent PD penetrating one or more of the thin layersconstituting the vertical layer 150 may be formed. Referring to FIG. 77, the penetrating dent PD may be formed to allow the capping layer CPLto remain below the penetrating dent PD. Referring to FIG. 78 , anunder-cut region UC0 extended by, for example, isotropically etching thesemiconductor spacer 165 exposed by the penetrating dent PD may beformed. Referring to FIGS. 79 and 80 , the under-cut region 77 may becompleted by, for example, isotropically etching the vertical layer 155.

Although FIGS. 79 and 80 may illustrate the method described withreference to FIG. 72 , the under-cut region 77 may be formed using thefabricating methods according to example embodiments described withreference to FIGS. 70-75 . The protective layer spacer PS may be removedwhile the vertical layer 155 is isotropically etched. For example, ifthe protective layer spacer PS is formed of a silicon nitride layer,protective layer spacer PS may be removed while the charge storing layerCL described with reference to FIG. 72 is etched. If the protectivelayer spacer PS is formed of a silicon oxide layer, protective layerspacer PS may be removed while the tunnel insulating layer TIL and thecapping layer CPL described with reference to FIG. 73 are etched.

Because of the extended under-cut region UC0, a height differencebetween the bottom surfaces of the vertical pattern 155 and thesemiconductor spacer 165 may be reduced as compared to exampleembodiments described with reference to FIGS. 73 and 75 . Referring toFIG. 80 , the under-cut region 77 may be more expansive than accordingto example embodiments described with reference to FIGS. 73 and 75 .This expansion of the under-cut region 77 may allow the secondsemiconductor layer 170 to conformally cover the inner walls of theunder-cut region 77 with less difficulty. Due to the expansion of theunder-cut region 77, void 89, which is not completely filled by thesecond semiconductor layer 170, may be formed in the under-cut region77.

Referring to FIGS. 81 and 82 , according to example embodiments of theinventive concepts, a penetrating dent PD may be formed to penetrate thevertical layer 150 and expose the top surface of the substrate 10.Referring to FIG. 81 , as a top surface of the substrate 10 exposed bythe penetrating dent PD is etched during the forming of an extendedunder-cut region UC0, the extended penetrating dent PDe may be formedbelow the vertical pattern 155. Similarly to example embodimentsdescribed with respect to FIGS. 76-80 , a void 89 may be formed in thesecond semiconductor layer 170. Referring to FIG. 82 , the void 89 mayinclude an upper void 89 a in the under-cut region 77 and a lower void89 b in the extended penetrating dent PDe. According to exampleembodiments, the void 89 may be completely or partially filled by aninsulation material (e.g., a silicon oxide layer).

According to example embodiments, a re-crystallization process for thesemiconductor spacer 165 and the second semiconductor layer 170 may beperformed (e.g., after the forming of the second semiconductor layer170). A density of crystal defects in the semiconductor spacer 165 andthe second semiconductor layer 170 may be reduced by there-crystallization process. For example, if the semiconductor spacer 165and the second semiconductor layer 170 are formed of polycrystallinesilicon, the re-crystallization process may increase grain sizes or mayform single crystal structures. The re-crystallization process may beperformed using at least one of thermal treatment techniques, laserannealing techniques, and/or epitaxial techniques. If the substrate 10is a single crystal wafer, the substrate 10 may have less crystaldefects than the semiconductor spacer 165 and the second semiconductorlayer 170 on the average.

FIG. 83 is a cross-sectional diagram illustrating a current path in athree-dimensional semiconductor device described with reference to FIGS.70-82 . As described with reference to FIG. 68 , in case of thethree-dimensional semiconductor device described with reference to FIGS.1-21 , because of the presence of the vertical pattern 155 extendinginto a top surface of the substrate 10, a current path P1 passingthrough the impurity region 240 may lengthen. According to exampleembodiments illustrated in FIG. 83 , because the second semiconductorlayer 170 and/or the semiconductor body portion 175 may be formedadjacent to the lowermost conductive pattern 230 by the under-cut region77, a current path P2 may be closer to the lowermost conductive pattern230 than the current path P1 shown in FIG. 68 . Accordingly, accordingto example embodiments, lengthening of the current path and exponentialincrease of electrical resistance may be prevented and/or reduced.

FIGS. 84-90 are cross-sectional diagrams illustrating exampleembodiments with respect to forming an under-cut region 77 describedwith reference to FIG. 24 . Three-dimensional semiconductor devicesincluding the under-cut region 77 on a bottom surface of the verticalpattern 155 and methods of fabricating the semiconductor devices may bedescribed. Methods of forming the under-cut region 77 and structuresaccording thereto are not limitedly applied to the structure shown inFIG. 24 . Those skilled in the art may easily apply the inventiveconcepts according to example embodiments related to the under-cutregion 77 and an expansive description may be omitted. Furthermore, eachof the following described methods may be applied instead to the methodsof fabricating described with reference to FIGS. 3-6 and/or FIGS. 13-14. Other methods may be performed based on following methods (e.g., stepsdescribed with reference to FIGS. 7-11 and/or FIGS. 15-21 ).

Referring to FIG. 84 , a mold structure 100 including an insulatinglayer 121 and a sacrificial layer 131 may be formed on a substrate 10.An opening 105 penetrating the mold structure 100 to expose a topsurface of the substrate 10 may be formed. A vertical layer 150 and afirst semiconductor layer 160 may be formed on the inner wall of theopening 105 (e.g., sequentially formed). A protective layer spacer PSexposing the top surface of the first semiconductor layer 160 at thebottom of the opening 105 may be formed on a sidewall of the firstsemiconductor layer 160.

The mold structure 100 may be substantially identical to that of exampleembodiments described with reference to FIG. 1 . The insulating layer121 and the sacrificial layer 131 may illustrate a portion of the moldstructure 100 and the mold structure 100 may further include moreinsulating layers and sacrificial layers as shown in FIG. 1 .

The opening 105 may be formed with, for example, a hole shape (e.g.,similar to FIG. 2 ) and/or to include a portion of a hexahedral shape(e.g., similar to FIG. 12 ). According to example embodiments, duringthe forming of the opening 105, the top surface of the substrate 10 maybe recessed. The bottom surface of the opening 105 may be lower than theuppermost surface of the substrate 10 contacting the bottom surface ofthe insulating layer 121. The recess of the substrate 10 may formed byover-etch of the opening 105. The recess of the substrate 10 maycontribute to improving structural stability of the vertical pattern155.

The vertical layer 150 and the first semiconductor layer 160 may beformed to substantially and conformally cover the sidewall and bottomsurface of the opening 105. A sum of deposition thicknesses of thevertical layer 150 and the first semiconductor layer 160 may be lessthan the half of the width of the opening 105. The opening 105 may notbe completely filled by the vertical layer 150 and the firstsemiconductor layer 160.

The vertical layer 150 and the first semiconductor layer 160 may beformed as the vertical structure VS according to example embodimentsdescribed with reference to FIGS. 28-43 . For example, the verticallayer 150 may include a capping layer CPL, a charge storing layer CL anda tunnel insulating layer TIL, which may be deposited (e.g.,sequentially deposited). A material and property of each of the cappinglayer CPL, the charge storing layer CL and the tunnel insulating layerTIL may be substantially identical to example embodiments described withreference to FIGS. 28-43 . The first semiconductor layer 160 may be apolycrystalline silicon layer.

The protective layer spacer PS may include at least one material withetch selectivity to the first semiconductor layer 160. For example, theprotective layer spacer PS may be a silicon oxide layer and/or a siliconnitride layer. The forming of the protective layer spacer PS may includeexposing the top surface of the first semiconductor layer 160 at thebottom of the opening 105 by, for example, anisotropically etching thestructure with the protective layer (e.g., after the forming of aprotective layer on the structure including the first semiconductorlayer 160). The protective layer may be formed using, for example, CVDand/or ALD. A thickness of the protective layer may be less than thehalf of the width of a gap region defined by the first semiconductorlayer 160.

Referring to FIGS. 85-88 , by etching the first semiconductor layer 160and the vertical layer 150 (e.g., sequentially etching), an under-cutregion exposing a portion of the sidewall and the bottom surface of thevertical layer 150 may be formed. The forming of the under-cut region,as shown in FIG. 85 may include forming a preliminary under-cut regionUC0 that exposes the surface of the tunnel insulating layer TIL by, forexample, etching the first semiconductor layer 160 to form asemiconductor spacer 165. For example, the under-cut region UC0 may beformed by isotropically etching the bottom region of the firstsemiconductor layer 160 using the protective layer spacer PS as an etchmask. According to example embodiments, the first semiconductor layer160 may be isotropically etched by, for example, a dry etch methodwithout plasma. Because the isotropic etch method may be applied, asshown in the dotted line, the exposed surface of the first semiconductorlayer 160 may extend in all directions as an etch process progresses.The bottom surface of the semiconductor spacer 165 may be further spacedfrom that of the opening 105 than that of the protective layer spacerPS. The bottom surface of the semiconductor spacer 165 may have, forexample, a rounded shape using the isotropic etch method.

The isotropic dry etching may be performed using, for example, (1) afirst gas including fluorine atoms, (2) a second gas including chlorineatoms, and/or (3) a carrier gas including at least one of argon, heliumor nitrogen. According to example embodiments, the first gas may be CF₄and/or CHF₃, and the second gas may be Cl₂. According to exampleembodiments, the first gas may be CF₄, CHF₃, C₂F₆, CCl₂F₂, CH₂F₂, NF₃and/or SiF₄, and the second gas may be Cl₂, BCl₃, and/or HCl. Accordingto example embodiments, during the isotropic dry etching, etching gasesincluding HBr, oxygen, and/or hydrogen may be used.

The isotropic dry etch may be performed under a pressure of less thanabout 1 atmospheric pressure and a temperature of about 200° C. to about700° C. For example, the isotropic dry etching may be performed under apressure of about 10 Torr to about 300 Torr and a temperature of about350° C. to about 500° C. The dry etch may not use plasma so that damageof the first semiconductor layer 160 and/or the vertical layer 150 dueto plasma may be prevented and/or reduced. Isotropic etch of the firstsemiconductor layer 160 may be possible. If an aspect ratio of theopening 105 is large, isotropic dry etch of the first semiconductorlayer 160 may be effectively performed.

Referring to FIG. 86 , a surface of the charge storing layer CL defininga first under-cut region UC1 may be exposed by etching the tunnelinsulating layer TIL exposed through the preliminary under-cut regionUC0. Referring to FIG. 87 , a surface of the capping layer CPL defininga second under-cut region UC2 may be exposed by etching the chargestoring layer CL exposed through the first under-cut region UC1.Referring to FIG. 88 , the under-cut region 77 may be completed byetching the capping layer CPL exposed through the second under-cutregion UC2 to expose the bottom surface and sidewall of the substrate10.

The etching of the tunnel insulating layer TIL, the charge storing layerCL, and the capping layer CPL may be performed using, for example, a wetetch method. According to example embodiments of the inventive concepts,the tunnel insulating layer TIL and the capping layer CPL may be, forexample, a silicon oxide layer and the charge storing layer CL may be,for example, a silicon nitride layer. The tunnel insulating layer TILand the capping layer CPL may be isotropically etched using, forexample, an etchant with phosphoric acid. The above-mentioned kinds ofthin layers and kinds of etchants used for the thin layers are examplesto describe the inventive concepts of example embodiments, and may bediversely modified.

The protective layer spacer PS may be removed during the etching of thevertical layer 150. For example, if the protective layer spacer PS is asilicon oxide layer, the protective layer spacer PS may be removed by,for example, hydrofluoric acid used for etching the tunnel insulatinglayer TIL and/or the capping layer CPL. If the protective layer spaceris a silicon nitride layer, the protective layer spacer may be, forexample, removed by phosphoric acid used for etching the charge storinglayer CL.

According to example embodiments, etching of the tunnel insulating layerTIL, the charge storing layer CL and the capping layer CPL may affect anetch profile of a previously etched thin layer. For example, ifphosphoric acid is used to etch the charge storing layer CL, the exposedsurface of the semiconductor spacer 165 may be partially etched by thephosphoric acid. Shapes of the semiconductor spacer 165 shown in FIGS.85 and 88 may be different from each other. The bottom edge of thesemiconductor pattern shown in FIG. 88 may be, for example, rounder thanthat of the semiconductor pattern of FIG. 85 . Influence of thefollowing etching step for an etch profile of a thin layer may besimilarly shown in the tunnel insulating layer TIL and the chargestoring layer CL. The etch profiles of FIGS. 84-88 are examples used todescribe the influence of the following etch step, and actual etchprofile may be diversely modified by an etch process recipe.

According to example embodiments, if the tunnel insulating layer TIL andthe capping layer CPL are formed of materials without effectively largeetch selectivity, the tunnel insulating layer TIL may be additionallyetched while the capping layer CPL is etched. For example, if all thetunnel insulating layer TIL and the capping layer CPL are formed of asilicon oxide layer, the tunnel insulating layer TIL may be etched twiceduring the etch methods described with reference to FIGS. 86 and 88 ,and the capping layer CPL may be etched once during the etch methodsdescribed with reference to FIG. 88 . The bottom region of the tunnelinsulating layer TIL may protrude downward below the charge storinglayer CL as shown in FIG. 87 , but during the etching of the cappinglayer CPL, may be additionally etched, so that may be recessed upwardlybetween the charge storing layer CL and the semiconductor spacer 165 asillustrated in FIG. 88 . Referring to FIG. 88 , an etch profile of thebottom surface of the vertical pattern 155 may be non-uniform. Thecharge storing layer CL may protrude further downward towards thesubstrate 10 than the capping layer CPL and the tunnel insulating layerTIL, and the bottom surface of the capping layer CPL may be moreadjacent to the top surface of the substrate 10 below the bottom of thetunnel insulating layer TIL than the bottom of the tunnel insulatinglayer TIL.

Referring to FIGS. 89 and 90 , a second semiconductor layer 170 coveringthe bottom surface and the sidewall of the substrate exposed through theunder-cut region 77 may be formed. A buried insulating layer 180 may beformed on the structure to bury at least a portion of the opening 105.The second semiconductor layer 170 may be a semiconductor material(e.g., polycrystalline silicon) formed using a deposition technique. Thesecond semiconductor layer 170 may extend upwardly from the under-cutregion 77 to cover the inner wall of the semiconductor spacer 165 in themold structure 100. A width and height of the under-cut region 77 may begreater than a width of an empty region defined by the inner wall of thesecond semiconductor layer 170. As shown in FIG. 90 , void 89 notcompletely filled by the buried insulating layer 180 may be formed inthe under-cut region 77.

According to example embodiments, a re-crystallization process for thesemiconductor spacer 165 and the second semiconductor layer 170 may beperformed (e.g., after the forming of the second semiconductor layer170). Density of crystal defects in the semiconductor spacer 165 and thesecond semiconductor layer 170 may be reduced by the re-crystallizationprocess. For example, if the semiconductor spacer 165 and the secondsemiconductor layer 170 are formed of polycrystalline silicon, there-crystallization process may increase their grain sizes or may formsingle crystal structures. The re-crystallization process may beperformed using at least one of thermal treatment techniques, laserannealing techniques, and epitaxial techniques. If the substrate 10 is asingle crystal wafer, the substrate 10 may have less crystal defectsthan the semiconductor spacer 165 and the second semiconductor layer 170on average.

FIG. 91 is a cross-sectional diagram illustrating a current path in athree-dimensional semiconductor device described with reference to FIGS.84-90 . As described with reference to FIG. 68 , in a three-dimensionalsemiconductor device described with reference to FIGS. 1-21 , because ofthe presence of the vertical pattern 155 extending into a top surface ofthe substrate 10, a current path P1 passing through the impurity region240 may lengthen. Referring to FIG. 91 , according to exampleembodiments, because the second semiconductor layer 170 or thesemiconductor body portion 175 may be formed adjacent to the lowermostconductive pattern 230 due to the under-cut region 77, a current path P2may be closer to the lowermost conductive pattern 230 than the currentpath P1 illustrated in FIG. 68. According to example embodiments,lengthening of the current path and exponential increase of electricalresistance may be prevented and/or reduced.

FIG. 92 is a block diagram illustrating memory cards 1200 includingflash memory devices 1210 according to example embodiments of theinventive concepts. Referring to FIG. 92 , the memory card 1200 forsupporting a data storage capability of high capacity may include aflash memory device 1210, for example, including a 3D memory device asdescribed with respect to example embodiments illustrated in FIGS. 1-91. The memory card 1200 according to example embodiments of the inventiveconcepts may include a memory controller 1220 controlling general dataexchanges between a host and the flash memory device 1210.

A SRAM 1221 may be used as an operating memory of a processing unit1222. A host interface 1223 may include a data exchange protocol of ahost connected to a memory card 1200. An error correction block 1224 maydetect and correct errors included in data read from a multi-bit flashmemory device 1210. A memory interface 1225 may interface with the flashmemory device 1210 of example embodiments of the inventive concepts. Aprocessing unit 1222 may perform general control operations for dataexchange of the memory controller 1220. Although not shown in thedrawing, it is apparent to those skilled in the art that the memory card1200 may further include ROM (not shown) storing code data to interfacewith a host.

FIG. 93 is a block diagram illustrating information processing systems1300 including flash memory systems 1310 according to exampleembodiments of the inventive concepts. Referring to FIG. 93 , the flashmemory system 1310 may be mounted on an information processing system,for example, a mobile device and/or a desktop computer. The informationprocessing system 1300 may include a flash memory system 1310, a modem1320, a central processing unit (CPU) 1330, a RAM 1340, and a userinterface 1350, electrically connected to a system bus 1360. The flashmemory system 1310 may be configured substantially identical to thememory system and/or flash memory system described with respect to FIG.92 . Data processed by the CPU 1330 and/or input from the outside may bestored in the flash memory system 1310. A memory system 1310 may be asolid state drive SSD. The information processing system 1300 may stablystore a large amount of data in the flash memory system 1310. Asreliability of the information processing system 1300 may be increased,the flash memory system 1310 may conserve resources used for errorcorrection, and a data exchange function of high speed may be providedto the information processing system 1310. Although not shown in thedrawing, it is apparent to those of ordinary skill in the art that theinformation processing system 1300 of example embodiments of theinventive concepts may include an application chipset, a camera imageprocessor (CIS), and/or an input/output device.

A flash memory device and/or a memory system of example embodiments ofthe inventive concepts may be mounted using various kinds of packages.For instance, the flash memory device and/or the memory system may bemounted with packages such as Package on Package (PoP), Ball Grid Arrays(BGA), Chip Scale Packages (CSP), Plastic Leaded Chip Carrier (PLCC),Plastic Dual In-line Package (PDIP), Die in Waffle Pack, Die in WaferForm, Chip On Board (COB), Ceramic Dual In-line Package (CERDIP),Plastic Metric Quad Flat Pack (MQFP), Thin Quad Flat Pack (TQFP), SmallOutline Integrated Circuit (SOIC), Shrink Small Outline Package (SSOP),Thin Small Outline Package (TSOP), System In Package (SIP), Multi ChipPackage (MCP), Wafer-level Fabricated Package (WFP), and/or Wafer-levelProcessed Stack Package (WSP).

According to example embodiments, a vertical pattern and the horizontalpattern may between a conductive pattern and a semiconductor pattern andmay be used as layers for storing information. The vertical pattern maybe formed in an opening (e.g., a vertical gap region) before forming ofthe semiconductor pattern, and the horizontal pattern and the conductivepattern may be formed in a recess region (e.g., a horizontal gap region)after the forming of the semiconductor pattern. Accordingly,three-dimensional semiconductor devices according to example embodimentsof the inventive concepts may not be restricted to the technicallimitations of a punch-and-plug technique according to a storage-firstmethod described, for example, with reference to FIG. 47 . Theconductive pattern according to example embodiments of the inventiveconcepts may be formed of a metallic material. Because the verticalpattern (e.g., a part of layers for storing information) may be formedin a recess region, a thickness of the conductive pattern according toexample embodiments of the inventive concepts may be increased over aplug-first method described, for example, with reference to FIG. 48 .

According to example embodiments of the inventive concepts, a crossingstructure with horizontally and vertically extended portions may beprovided between the sidewalls of the conductive pattern and thesemiconductor pattern. The crossing structure may alleviate thetechnical limitations according to the storage-first method and theplug-first method.

According to example embodiments of the inventive concepts, asdescribed, for example, with reference to FIGS. 1-21 , even if a memorygate insulating layer is formed to have a vertical pattern and ahorizontal pattern, the semiconductor pattern (e.g., a selection activepattern) used as an active region of the selection transistors maycontact the semiconductor substrate without the intervention of aninsulation material. Accordingly, a reduction of an operating currentand resistance increase of a string described, for example, withreference to FIG. 68 may be prevented and/or reduced.

According to example embodiments, an under-cut region may be formedbelow a vertical pattern, and a semiconductor material connecting thesubstrate with the semiconductor spacer may be formed. Accordingly, areduction of an operating current and resistance increase of a stringdescribed, for example, with reference to FIG. 68 may be preventedand/or reduced. According to example embodiments, the under-cut regionmay be formed using, for example, a dry etch and/or wet etch techniquewithout using plasma. Accordingly, etch damage of the semiconductorspacer due to plasma may be prevented and/or reduced.

While example embodiments have been particularly shown and described, itwill be understood by one of ordinary skill in the art that variationsin form and detail may be made therein without departing from the spiritand scope of the claims.

What is claimed is:
 1. A semiconductor memory device comprising: asubstrate; a vertical structure extending in a first directionperpendicular to a top surface of the substrate, the vertical structureincluding a buried pattern, a channel layer, a tunneling layer, a chargestorage layer, and a blocking layer; and a horizontal structureextending in a second direction parallel to the top surface of thesubstrate, the horizontal structure including a high-k dielectric layer,a metal nitride layer, and a tungsten pattern.
 2. The semiconductormemory device of claim 1, wherein the horizontal structure surrounds thevertical structure.
 3. The semiconductor memory device of claim 1,wherein the channel layer surrounds a sidewall of the buried pattern,and wherein the tunneling layer, the charge storage layer, and theblocking layer surround a sidewall of the channel layer.
 4. Thesemiconductor memory device of claim 1, wherein the high-k dielectriclayer covers top and bottom surfaces of the metal nitride layer.
 5. Thesemiconductor memory device of claim 1, wherein the metal nitride layercovers top and bottom surfaces of the tungsten pattern.
 6. Thesemiconductor memory device of claim 1, further comprising a pluralityof interlayer insulating layers stacked on the substrate, wherein thehorizontal structure is located between adjacent ones of the interlayerinsulating layers.
 7. The semiconductor memory device of claim 6,wherein each of the interlayer insulating layers has a first sidewalladjacent to the vertical structure and a second sidewall opposite to thefirst sidewall, and wherein a portion of the high-k dielectric layercovers the second sidewalls of the adjacent ones of the interlayerinsulating layers.
 8. The semiconductor memory device of claim 1,wherein the high-k dielectric layer includes at least one of an aluminumoxide layer, a hafnium oxide layer, a zirconium oxide layer, a tantalumoxide layer, and a titanium oxide layer.
 9. A semiconductor memorydevice comprising: a tungsten pattern extending in a first direction; achannel layer extending in a second direction perpendicular to the firstdirection and penetrating the tungsten pattern; a buried pattern in thechannel layer; a tunneling layer, a charge storage layer, and a blockinglayer between the tungsten pattern and the channel layer; and a high-kdielectric layer and a metal nitride layer between the blocking layerand the tungsten pattern, wherein the tunneling layer, the chargestorage layer, and the blocking layer extend along a sidewall of thechannel layer in the second direction, and wherein the high-k dielectriclayer and the metal nitride layer extend in the first direction andcover top and bottom surfaces of the tungsten pattern.
 10. Thesemiconductor memory device of claim 9, wherein the channel layerincludes a polycrystalline silicon material.
 11. The semiconductormemory device of claim 9, wherein the channel layer has a cylindricalshape.
 12. The semiconductor memory device of claim 9, wherein adielectric constant of the blocking layer is larger than a dielectricconstant of the tunneling layer.
 13. The semiconductor memory device ofclaim 9, further comprising a plurality of interlayer insulating layersstacked in the second direction, wherein the tungsten pattern is locatedbetween adjacent ones of the interlayer insulating layers.
 14. Thesemiconductor memory device of claim 13, wherein each of the interlayerinsulating layers has a first sidewall adjacent to the channel layer anda second sidewall opposite to the first sidewall, and wherein a portionof the high-k dielectric layer covers the second sidewalls of theadjacent ones of the interlayer insulating layers.
 15. The semiconductormemory device of claim 9, wherein the tunneling layer includes at leastone silicon oxide layer, wherein the charge storing layer includes aninsulating layer having intrinsic conductive nano particles or a higherdensity of trap sites than a silicon oxide layer, and wherein theblocking layer includes at least one of an aluminum oxide layer, ahafnium oxide layer, a zirconium oxide layer, a tantalum oxide layer, atitanium oxide layer, a silicon nitride layer, a silicon oxynitridelayer, and a silicon oxide layer.
 16. A data storage system comprising:a plurality of semiconductor memory devices; and a controller that isconfigured to control the semiconductor memory devices, wherein each ofthe semiconductor memory devices comprises: a substrate; a verticalstructure extending in a first direction perpendicular to a top surfaceof the substrate, the vertical structure including a buried pattern, achannel layer, a tunneling layer, a charge storage layer, and a blockinglayer; and a horizontal structure extending in a second directionparallel to the top surface of the substrate, the horizontal structureincluding a high-k dielectric layer, a metal nitride layer, and atungsten pattern.
 17. The data storage system of claim 16, wherein thehorizontal structure surrounds the vertical structure.
 18. The datastorage system of claim 16, wherein the high-k dielectric layer isbetween the blocking layer and the metal nitride layer.
 19. The datastorage system of claim 16, wherein the high-k dielectric layer coverstop and bottom surfaces of the metal nitride layer.
 20. The data storagesystem of claim 16, wherein the channel layer has a cylindrical shape,and wherein the buried pattern is in the channel layer.